ORCID Profile
0000-0002-7335-2168
Current Organisations
Peter MacCallum Cancer Centre
,
Peter MacCallum Cancer Institute
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Springer Science and Business Media LLC
Date: 15-04-2013
DOI: 10.1038/SREP01659
Publisher: Springer Science and Business Media LLC
Date: 10-08-2023
DOI: 10.1038/S41467-023-40315-9
Abstract: Despite initial responses to hormone treatment, metastatic prostate cancer invariably evolves to a lethal state. To characterize the intra-patient evolutionary relationships of metastases that evade treatment, we perform genome-wide copy number profiling and bespoke approaches targeting the androgen receptor (AR) on 167 metastatic regions from 11 organs harvested post-mortem from 10 men who died from prostate cancer. We identify erse and patient-unique alterations clustering around the AR in metastases from every patient with evidence of independent acquisition of related genomic changes within an in idual and, in some patients, the co-existence of AR -neutral clones. Using the genomic boundaries of pan-autosome copy number changes, we confirm a common clone of origin across metastases and diagnostic biopsies, and identified in in idual patients, clusters of metastases occupied by dominant clones with erged autosomal copy number alterations. These autosome-defined clusters are characterized by cluster-specific AR gene architectures, and in two index cases are topologically more congruent than by chance ( p -values 3.07 × 10 −8 and 6.4 × 10 −4 ). Integration with anatomical sites suggests patterns of spread and points of genomic ergence. Here, we show that copy number boundaries identify treatment-selected clones with putatively distinct lethal trajectories.
Publisher: Bioscientifica
Date: 2017
DOI: 10.1530/ERC-17-0306
Abstract: Pheochromocytomas (PC) and paragangliomas (PGL) are endocrine tumors for which the genetic and clinicopathological features of metastatic progression remain incompletely understood. As a result, the risk of metastasis from a primary tumor cannot be predicted. Early diagnosis of in iduals at high risk of developing metastases is clinically important and the identification of new biomarkers that are predictive of metastatic potential is of high value. Activation of TERT has been associated with a number of malignant tumors, including PC/PGL. However, the mechanism of TERT activation in the majority of PC/PGL remains unclear. As TERT promoter mutations occur rarely in PC/PGL, we hypothesized that other mechanisms – such as structural variations – may underlie TERT activation in these tumors. From 35 PC and four PGL, we identified three primary PCs that developed metastases with elevated TERT expression, each of which lacked TERT promoter mutations and promoter DNA methylation. Using whole genome sequencing, we identified somatic structural alterations proximal to the TERT locus in two of these tumors. In both tumors, the genomic rearrangements led to the positioning of super-enhancers proximal to the TERT promoter, that are likely responsible for the activation of the normally tightly repressed TERT expression in chromaffin cells
Publisher: American Association for Cancer Research (AACR)
Date: 04-2023
DOI: 10.1158/1078-0432.22490194.V1
Abstract: Supplementary material
Publisher: Springer Science and Business Media LLC
Date: 05-03-2015
DOI: 10.1038/BJC.2015.80
Publisher: Elsevier BV
Date: 10-2022
DOI: 10.1016/J.PATHOL.2022.02.010
Abstract: Droplet digital PCR (ddPCR) has been demonstrated in many research studies to be a sensitive method in the analysis of circulating tumour DNA (ctDNA) for identifying mutations and tracking disease. The transition of ddPCR into the diagnostic setting requires a number of critical steps including the assessment of accuracy and precision and ultimately implementation into clinical use. Here we present the clinical validation of ddPCR for the detection of BRAF mutations (V600E and V600K) from plasma. We describe the performance characteristics assessed including the limit of blank, limit of detection, ruggedness, accuracy, precision and the effect of the matrix. Overall, each assay could achieve a limit of detection of 0.5% variant allele fraction and was highly accurate, with 100% concordance of results obtained from routine diagnostic testing of formalin fixed tumour s les or reference controls (n=36 for BRAF V600E and n=30 for BRAF V600K). Inter-laboratory reproducibility across 12 plasma s les for each assay was also assessed and results were 100% concordant. Overall, we report the successful validation and translation of a ddPCR assay into clinical routine practice.
Publisher: Springer Science and Business Media LLC
Date: 13-05-2014
Publisher: The Endocrine Society
Date: 04-2007
DOI: 10.1210/EN.2006-0965
Publisher: Cold Spring Harbor Laboratory
Date: 02-05-2019
DOI: 10.1101/623223
Abstract: Antigen-recognition by CD8 + T cells is governed by the pool of peptide antigens presented on the cell surface in the context of HLA class I complexes. Recent studies have shown not only a high degree of plasticity in the immunopeptidome, but also that a considerable fraction of all presented peptides is generated through proteasome-mediated splicing of non-contiguous regions of proteins to form novel peptide antigens. Here we used high-resolution mass-spectrometry combined with new bioinformatic approaches to characterize the immunopeptidome of melanoma cells in the presence or absence of interferon-γ. In total, we identified more than 60,000 peptides from a single patient derived cell line (LM-MEL-44) and demonstrated that interferon-γ induced marked changes in the peptidome with an overlap of only ∼50% between basal and treated cells. Around 6-8% of the peptides were identified as cis -spliced peptides, and 2213 peptides (1827 linear, 386 cis -spliced peptides) were derived from known melanoma-associated antigens. These peptide antigens were equally distributed between the constitutive and interferon-γ induced peptidome. We next examined additional HLA-matched patient derived cell lines to investigate how frequently these peptides were identified and found that a high proportion of both linear and spliced peptides were conserved between in idual patient tumors, drawing on data amassing to over 100,000 peptide sequences from these extended data sets. Moreover, several of these peptides showed in vitro immunogenicity across multiple melanoma patients. These observations highlight the breadth and complexity of the repertoire of immunogenic peptides that can be exploited therapeutically and suggest that spliced peptides are a major new class of tumor antigens.
Publisher: Springer Science and Business Media LLC
Date: 23-06-2023
Publisher: Public Library of Science (PLoS)
Date: 22-07-2013
Publisher: Springer Science and Business Media LLC
Date: 12-2014
DOI: 10.1038/BJC.2014.511
Publisher: Cold Spring Harbor Laboratory
Date: 03-09-2022
DOI: 10.1101/2022.09.01.506183
Abstract: Despite initial responses to hormone treatment, metastatic prostate cancer invariably evolves to a lethal state. To characterize the intra-patient relationships of metastases that evade treatment, we performed genomewide copy number profiling and bespoke approaches targeting the androgen receptor (AR) on 142 metastatic regions from 10 organs harvested post-mortem from nine men who died from prostate cancer. We identified erse and patient-unique alterations clustering around the AR in metastases from every patient with evidence of independent acquisition of related genomic changes within an in idual and, in some patients, the co-existence of AR -neutral clones. Using the genomic boundaries of pan-autosome copy number change, we confirmed a common clone of origin across metastases and diagnostic biopsies and identified in in idual patients, clusters of metastases occupied by dominant clones with erged autosomal copy number alterations. Autosome-defined clusters were characterized by cluster-specific AR gene architectures that in two index cases were topologically more congruent than by chance ( p -values 0.03, 3.07×10 -8 ). Integration with anatomical site suggested patterns of spread and points of genomic ergence. Copy number boundaries identified treatment-selected clones with putatively distinct lethal trajectories. Lethal prostate cancer evolves from a single clone of origin and upon a treatment-mediated selection, progresses to lethal disease via a limited number of related clones harboring patient-unique androgen receptor gene architectures.
Publisher: The Endocrine Society
Date: 2010
DOI: 10.1210/EN.2009-0590
Abstract: During the stress response and metabolic fasting, glucocorticoids acting via the glucocorticoid receptor (GR) stimulate hepatic glucose production by activating specific gluconeogenic enzyme target genes. To characterize novel direct GR-regulated hepatic target genes under glucocorticoid control, we performed a whole genome gene expression microarray using dexamethasone-treated GR-null mice. Strongly induced previously characterized genes included phosphoenolpyruvate carboxykinase, serine dehydratase, tyrosine oxygenase, lipin 1, metallothionine, and cdkn1A. Novel induced genes included Ddit4, Fkbp5, Megf9, Sult1e1, and Sult1d1, and all were verified by real-time PCR. Sult1d1, a sulfotransferase, is a member of a large superfamily of detoxification enzymes and has an important role in the inactivation of endogenous dopamine-derived compounds, including the catecholamines. Treatment of primary mouse hepatocytes with dexamethasone for 6 h dramatically increased Sult1d1 mRNA levels, whereas cotreatment with RU-486, a GR antagonist, blocked induction by dexamethasone. Sult1d1 mRNA levels were also increased by dexamethasone in the kidney, a major site of Sult1d1 synthesis. Sult1d1 mRNA was localized by in situ hybridization to renal collecting ducts and was rapidly induced by glucocorticoids in renal inner medullary collecting duct (IMCD3) cells. Hepatic and renal Sult1d1 enzymatic activity was significantly induced in vivo in wild-type mice 6 h after dexamethasone treatment. Chromatin immunoprecipitation assay analysis upstream of the Sult1d1 gene promoter identified a glucocorticoid response element close to the neighboring glucocorticoid-responsive estrogen sulfotransferase Sult1e1 gene, indicating that both genes potentially share a common glucocorticoid response element. These results suggest that Sult1d1 in mice is directly induced by glucocorticoids and may attenuate elevated catecholamine activity during the stress response.
Publisher: American Association for Cancer Research (AACR)
Date: 13-01-2023
DOI: 10.1158/1078-0432.CCR-22-3094
Abstract: BRAF V600E mutant metastatic colorectal cancer represents a significant clinical problem, with combination approaches being developed clinically with oral BRAF inhibitors combined with EGFR-targeting antibodies. While compelling preclinical data have highlighted the effectiveness of combination therapy with vemurafenib and small-molecule EGFR inhibitors, gefitinib or erlotinib, in colorectal cancer, this therapeutic strategy has not been investigated in clinical studies. We conducted a phase Ib/II dose-escalation/expansion trial investigating the safety/efficacy of the BRAF inhibitor vemurafenib and EGFR inhibitor erlotinib. Thirty-two patients with BRAF V600E positive metastatic colorectal cancer (mCRC) and 7 patients with other cancers were enrolled. No dose-limiting toxicities were observed in escalation, with vemurafenib 960 mg twice daily with erlotinib 150 mg daily selected as the recommended phase II dose. Among 31 evaluable patients with mCRC and 7 with other cancers, overall response rates were 32% [10/31, 16% (5/31) confirmed] and 43% (3/7), respectively, with clinical benefit rates of 65% and 100%. Early ctDNA dynamics were predictive of treatment efficacy, and serial ctDNA monitoring revealed distinct patterns of convergent genomic evolution associated with acquired treatment resistance, with frequent emergence of MAPK pathway alterations, including polyclonal KRAS, NRAS, and MAP2K1 mutations, and MET lification. The Erlotinib and Vemurafenib In Combination Trial study demonstrated a safe and novel combination of two oral inhibitors targeting BRAF and EGFR. The dynamic assessment of serial ctDNA was a useful measure of underlying genomic changes in response to this combination and in understanding potential mechanisms of resistance.
Publisher: Oxford University Press (OUP)
Date: 13-06-2015
DOI: 10.1111/BJD.13756
Abstract: The clinical behaviour and prognosis of primary melanomas harbouring BRAF mutations is not fully understood. To investigate the effect of mutation status on primary melanoma growth rate and melanoma-specific survival (MSS). A prospective cohort of 196 patients with stage I-III primary cutaneous melanoma were followed for a median of 92 months, pre-dating the institution of BRAF inhibitor therapy. Clinicopathological variables were correlated with mutation status and hazard ratios (HRs) estimated for MSS. Of 196 tumours, 77 (39.2%) were BRAF V600E, 10 (5.1%) BRAF V600K and 33 (16.8%) were NRAS mutant. BRAF V600E mutant melanomas were associated with favourable clinical characteristics and tended to be slower growing compared with BRAF V600K, NRAS mutant or BRAF/NRAS wild-type tumours (0.12 mm per month, 0.61 mm per month, 0.36 mm per month and 0.23 mm per month, respectively P = 0.05). There were 39 melanoma deaths, and BRAF mutant melanomas were associated with poorer MSS in stage I-III disease [HR 2.60, 95% confidence interval (CI) 1.20-5.63 P = 0.02] and stage I-II disease (HR 3.39, 95% CI 1.12-10.22 P = 0.03) after adjusting for other prognostic variables. Considered separately, BRAF V600E mutant melanomas were strongly associated with MSS independently of thickness and nodal status (HR 3.89, 95% CI 1.67-9.09 P < 0.01) but BRAF V600K mutant tumours were not (HR 1.19, 95% CI 0.36-3.92 P = 0.77). The presence of a BRAF mutation does not necessarily 'drive' more rapid tumour growth but is associated with poorer MSS in patients with early-stage disease.
Publisher: Springer Science and Business Media LLC
Date: 04-03-2021
DOI: 10.1038/S41467-021-21576-8
Abstract: Although melanoma is initiated by acquisition of point mutations and limited focal copy number alterations in melanocytes-of-origin, the nature of genetic changes that characterise lethal metastatic disease is poorly understood. Here, we analyze the evolution of human melanoma progressing from early to late disease in 13 patients by s ling their tumours at multiple sites and times. Whole exome and genome sequencing data from 88 tumour s les reveals only limited gain of point mutations generally, with net mutational loss in some metastases. In contrast, melanoma evolution is dominated by whole genome doubling and large-scale aneuploidy, in which widespread loss of heterozygosity sculpts the burden of point mutations, neoantigens and structural variants even in treatment-naïve and primary cutaneous melanomas in some patients. These results imply that dysregulation of genomic integrity is a key driver of selective clonal advantage during melanoma progression.
Publisher: American Association for Cancer Research (AACR)
Date: 08-2020
DOI: 10.1158/1078-0432.CCR-19-3926
Abstract: Brain involvement occurs in the majority of patients with metastatic melanoma. The potential of circulating tumor DNA (ctDNA) for surveillance and monitoring systemic therapy response in patients with melanoma brain metastases merits investigation. This study examined circulating BRAF, NRAS, and c-KIT mutations in patients with melanoma with active brain metastases receiving PD-1 inhibitor–based therapy. Intracranial and extracranial disease volumes were measured using the sum of product of diameters, and response assessment performed using RECIST. Longitudinal plasma s les were analyzed for ctDNA over the first 12 weeks of treatment (threshold 2.5 copies/mL plasma). Of a total of 72 patients, 13 patients had intracranial metastases only and 59 patients had concurrent intracranial and extracranial metastases. ctDNA detectability was 0% and 64%, respectively, and detectability was associated with extracranial disease volume (P & 0.01). Undetectable ctDNA on-therapy was associated with extracranial response (P & 0.01) but not intracranial response. The median overall survival in patients with undetectable (n = 34) versus detectable (n = 38) ctDNA at baseline was 39.2 versus 10.6 months [HR, 0.51 95% confidence interval (CI), 0.28–0.94 P = 0.03] and on-therapy was 39.2 versus 9.2 months (HR, 0.32 95% CI, 0.16–0.63 P & 0.01). ctDNA remains a strong prognostic biomarker in patients with melanoma with brain metastases, especially in patients with concurrent extracranial disease. However, ctDNA was not able to detect or monitor intracranial disease activity, and we recommend against using ctDNA as a sole test during surveillance and therapeutic monitoring in patients with melanoma.
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.JMOLDX.2018.12.001
Abstract: The analysis of circulating tumor DNA provides a minimally invasive molecular interrogation that has the potential to guide treatment selection and disease monitoring. Here, the authors evaluated a custom UltraSEEK melanoma panel for the MassARRAY system, probing for 61 mutations over 13 genes. The analytical sensitivity and clinical accuracy of the UltraSEEK melanoma panel was compared with droplet digital PCR. The blinded analysis of 68 mutations detected in 48 plasma s les from stage IV melanoma patients revealed a concordance of 88% between the two platforms. Further comparison of both methods for the detection of BRAF V600E mutations in 77 plasma s les demonstrated a Cohen's κ of 0.826 (bias-corrected and accelerated 95% CI, 0.669-0.946). These results indicate that the UltraSEEK melanoma panel is as sensitive as droplet digital PCR for the detection of circulating tumor DNA in this cohort of patients but highlight the need for detected variants to be confirmed orthogonally to mitigate any false-positive results. The MassARRAY system enables rapid and sensitive genotyping for the detection of multiple melanoma-associated mutations in plasma.
Publisher: Informa UK Limited
Date: 13-01-2012
Publisher: American Association for Cancer Research (AACR)
Date: 13-11-2020
DOI: 10.1158/1078-0432.CCR-20-2251
Abstract: We evaluated the predictive value of pretreatment ctDNA to inform therapeutic outcomes in patients with metastatic melanoma relative to type and line of treatment. Plasma circulating tumor DNA (ctDNA) was quantified in 125 s les collected from 110 patients prior to commencing treatment with immune checkpoint inhibitors (ICIs), as first- (n = 32) or second-line (n = 27) regimens, or prior to commencing first-line BRAF/MEK inhibitor therapy (n = 66). An external validation cohort included 128 patients commencing ICI therapies in the first- (N = 77) or second-line (N = 51) settings. In the discovery cohort, low ctDNA (≤20 copies/mL) prior to commencing therapy predicted longer progression-free survival (PFS) in patients treated with first-line ICIs [HR, 0.20 95% confidence interval (CI) 0.07–0.53 P & 0.0001], but not in the second-line setting. An independent cohort validated that ctDNA is predictive of PFS in the first-line setting (HR, 0.42 95% CI, 0.22–0.83 P = 0.006), but not in the second-line ICI setting. Moreover, ctDNA prior to commencing ICI treatment was not predictive of PFS for patients pretreated with BRAF/MEK inhibitors in either the discovery or validation cohorts. Reduced PFS and overall survival were observed in patients with high ctDNA receiving anti–PD-1 monotherapy, relative to those treated with combination anti–CTLA-4/anti–PD-1 inhibitors. Pretreatment ctDNA is a reliable indicator of patient outcome in the first-line ICI treatment setting, but not in the second-line ICI setting, especially in patients pretreated with BRAF/MEK inhibitors. Preliminary evidence indicated that treatment-naïve patients with high ctDNA may preferentially benefit from combined ICIs.
Publisher: Oxford University Press (OUP)
Date: 09-2013
DOI: 10.1373/CLINCHEM.2012.202390
Abstract: Formalin-fixed, paraffin-embedded (FFPE) tissues are routinely used for detecting mutational biomarkers in patients with cancer. A previous intractable challenge with FFPE DNA in genetic testing has been the high number of artifactual single-nucleotide changes (SNCs), particularly for the detection of low-level mutations. Pretreatment of FFPE DNA with uracil-DNA glycosylase (UDG) can markedly reduce these C:G& T:A SNCs with a small panel of licons. This procedure has implications for massively parallel sequencing approaches to mutation detection from DNA. We investigated whether sequence artifacts were problematic in licon-based massively parallel sequencing and what effect UDG pretreatment had on reducing these artifacts. We lified selected licons from lung cancer FFPE DNAs using the TruSeq Cancer Panel. SNCs occurring at a frequency & % were considered most likely to represent sequence artifacts and were enumerated for both UDG-treated and -untreated DNAs. Massively parallel sequencing of FFPE DNA s les showed multiple SNCs, predominantly C:G& T:A changes, with a significant proportion occurring above the BACKGROUND sequencing error (defined as 1%). UDG pretreatment markedly reduced C:G& T:A SNCs without affecting the detection of true somatic mutations. However, C:G& T:A changes within CpG dinucleotides were often resistant to the UDG treatment as a consequence of 5-methyl cytosine being deaminated to thymine rather than uracil. UDG pretreatment greatly facilitates the accurate discrimination of mutations in FFPE s les by use of licon-based approaches. This is particularly important when working with s les with low tumor purity or for the assessment of mutational heterogeneity in tumors.
Publisher: Elsevier BV
Date: 11-2018
Publisher: Springer Science and Business Media LLC
Date: 09-02-2017
DOI: 10.1038/SREP42259
Abstract: ALK, ROS1 and RET gene fusions are important predictive biomarkers for tyrosine kinase inhibitors in lung cancer. Currently, the gold standard method for gene fusion detection is Fluorescence In Situ Hybridization (FISH) and while highly sensitive and specific, it is also labour intensive, subjective in analysis, and unable to screen a large numbers of gene fusions. Recent developments in high-throughput transcriptome-based methods may provide a suitable alternative to FISH as they are compatible with multiplexing and diagnostic workflows. However, the concordance between these different methods compared with FISH has not been evaluated. In this study we compared the results from three transcriptome-based platforms (Nanostring Elements, Agena LungFusion panel and ThermoFisher NGS fusion panel) to those obtained from ALK, ROS1 and RET FISH on 51 clinical specimens. Overall agreement of results ranged from 86–96% depending on the platform used. While all platforms were highly sensitive, both the Agena panel and Thermo Fisher NGS fusion panel reported minor fusions that were not detectable by FISH. Our proof–of–principle study illustrates that transcriptome-based analyses are sensitive and robust methods for detecting actionable gene fusions in lung cancer and could provide a robust alternative to FISH testing in the diagnostic setting.
Publisher: Cold Spring Harbor Laboratory
Date: 04-2019
DOI: 10.1101/MCS.A003764
Abstract: Adrenocortical carcinoma is a rare malignancy with a poor prognosis and few treatment options. Molecular characterization of this cancer remains limited. We present a case of an adrenocortical carcinoma (ACC) in a 37-yr-old female, with dual lung metastases identified 1 yr following commencement of adjuvant mitotane therapy. As standard therapeutic regimens are often unsuccessful in ACC, we undertook a comprehensive genomic study into this case to identify treatment options and monitor disease progress. We performed targeted and whole-genome sequencing of germline, primary tumor, and both metastatic tumors from this patient and monitored recurrence over 2 years using liquid biopsy for ctDNA and steroid hormone measurements. Sequencing revealed the primary and metastatic tumors were hyperhaploid, with extensive loss of heterozygosity but few structural rearrangements. Loss-of-function mutations were identified in MSH2 , TP53 , RB1 , and PTEN , resulting in tumors with mismatch repair signatures and microsatellite instability. At the cellular level, tumors were populated by mitochondria-rich oncocytes. Longitudinal ctDNA mutation and hormone profiles were unable to detect micrometastatic disease, consistent with clinical indicators of disease remission. The molecular signatures in our ACC case suggested immunotherapy in the event of disease progression however, the patient remains free of cancer. The extensive molecular analysis presented here could be applied to other rare and/or poorly stratified cancers to identify novel or repurpose existing therapeutic options, thereby broadly improving diagnoses, treatments, and prognoses.
Publisher: Elsevier BV
Date: 04-2020
Publisher: Springer Science and Business Media LLC
Date: 17-02-2021
DOI: 10.1038/S41598-021-83436-1
Abstract: Low-coverage whole-genome sequencing (LC-WGS) can provide insight into oncogenic molecular changes. Serum extracellular vesicles (EV) represent a novel liquid biopsy source of tumoral DNA. This study compared copy number alteration (CNA) profiles generated from LC-WGS of formalin-fixed paraffin-embedded (FFPE) tumoral DNA and EV-DNA obtained from cancer patients. Patients with squamous cell carcinoma of the base of tongue (n = 3) and cutaneous squamous cell carcinoma (n = 2) were included. LC-WGS (0.5-1X coverage) was performed on FFPE-DNA and serum EV-DNA. Similarity between CNA profiles was analysed using QDNAseq. FFPE s les had a mean CNA of 31 (range 17–50) over 1.9 × 10 9 (range 1.0–2.6 × 10 9 ) bp in length, and EV s les had a mean CNA value of 17 (range 7–19) over 7.6 × 10 8 (range 2.9–15 × 10 8 ) bp in length. A mean of 8 (range 0–21) CNA over 5.9 × 10 8 (range 1.6–14 × 10 8 ) bp in length was found to overlap between EV and FFPE-derived s les per patient. Although the mean correlation efficient between s les was r = 0.34 (range − .08 to 0.99), this was not statistically significant ( p 0.05). Regions of highest deletion and duplication in FFPE s les were not well reflected in the EV-DNA. Selected CNA regions in EV-associated DNA were reflective of the primary tumor, however appreciation of global CNA and areas of most significant change was lost. The utility of LC-WGS of EV-derived DNA is likely limited to molecular alterations of known interest.
Publisher: American Association for Cancer Research (AACR)
Date: 04-2023
DOI: 10.1158/1078-0432.22490194
Abstract: Supplementary material
Publisher: Springer Science and Business Media LLC
Date: 16-06-2015
Publisher: Springer Science and Business Media LLC
Date: 27-07-2021
Publisher: Wiley
Date: 04-08-2014
DOI: 10.1111/PCMR.12295
Abstract: Activating mutations in the GTPase RAC1 are a recurrent event in cutaneous melanoma. We investigated the clinical and pathological associations of RAC1(P29S) in a cohort of 814 primary cutaneous melanomas with known BRAF and NRAS mutation status. The RAC1(P29S) mutation had a prevalence of 3.3% and was associated with increased thickness (OR=1.6 P = 0.001), increased mitotic rate (OR=1.3 P = 0.03), ulceration (OR=2.4 P = 0.04), nodular subtype (OR=3.4 P = 0.004), and nodal disease at diagnosis (OR=3.3 P = 0.006). BRAF mutant tumors were also associated with nodal metastases (OR=1.9 P = 0.004), despite being thinner at diagnosis than BRAF WT (median 1.2 mm versus 1.6 mm, P < 0.001). Immunohistochemical analysis of 51 melanomas revealed that 47% were immunoreactive for RAC1. Melanomas were more likely to show RAC1 immunoreactivity if they were BRAF mutant (OR=5.2 P = 0.01). RAC1 may therefore be important in regulating the early migration of BRAF mutant tumors. RAC1 mutations are infrequent in primary melanomas but may accelerate disease progression.
Publisher: American Association for Cancer Research (AACR)
Date: 14-12-2015
DOI: 10.1158/0008-5472.CAN-15-1877
Abstract: Merkel cell carcinoma (MCC) is an uncommon, but highly malignant, cutaneous tumor. Merkel cell polyoma virus (MCV) has been implicated in a majority of MCC tumors however, viral-negative tumors have been reported to be more prevalent in some geographic regions subject to high sun exposure. While the impact of MCV and viral T-antigens on MCC development has been extensively investigated, little is known about the etiology of viral-negative tumors. We performed targeted capture and massively parallel DNA sequencing of 619 cancer genes to compare the gene mutations and copy number alterations in MCV-positive (n = 13) and -negative (n = 21) MCC tumors and cell lines. We found that MCV-positive tumors displayed very low mutation rates, but MCV-negative tumors exhibited a high mutation burden associated with a UV-induced DNA damage signature. All viral-negative tumors harbored mutations in RB1, TP53, and a high frequency of mutations in NOTCH1 and FAT1. Additional mutated or lified cancer genes of potential clinical importance included PI3K (PIK3CA, AKT1, PIK3CG) and MAPK (HRAS, NF1) pathway members and the receptor tyrosine kinase FGFR2. Furthermore, looking ahead to potential therapeutic strategies encompassing immune checkpoint inhibitors such as anti-PD-L1, we also assessed the status of T-cell–infiltrating lymphocytes (TIL) and PD-L1 in MCC tumors. A subset of viral-negative tumors exhibited high TILs and PD-L1 expression, corresponding with the higher mutation load within these cancers. Taken together, this study provides new insights into the underlying biology of viral-negative MCC and paves the road for further investigation into new treatment opportunities. Cancer Res 75(24) 5228–34. ©2015 AACR.
Publisher: Future Medicine Ltd
Date: 05-2016
Abstract: Somatic mutations in the KRAS gene often occur in colorectal cancer (CRC) and are predictive for poor response to EGFR blockade therapy. Over the past decade, routine detection of KRAS mutations has been employed in many diagnostic centers using a range of methodological approaches including Sanger sequencing, pyrosequencing, high-resolution melt analysis and more recently, next-generation sequencing approaches. This article highlights the clinical relevance of KRAS-mutated CRCs, examines advantages and disadvantages of various detection methods and highlights the considerations that are critical for an accurate, rapid and efficient workflow to detect KRAS and other RAS mutations in CRC presently and in the future.
Publisher: Springer Science and Business Media LLC
Date: 24-06-2011
Abstract: Detection of mutations by DNA sequencing can be facilitated by scanning methods to identify licons which may have mutations. Current scanning methods used for the detection of germline sequence variants are laborious as they require post-PCR manipulation. High resolution melting (HRM) is a cost-effective rapid screening strategy, which readily detects heterozygous variants by melting curve analysis of PCR products. It is well suited to screening genes such as BRCA1 and BRCA2 as germline pathogenic mutations in these genes are always heterozygous. Assays for the analysis of all coding regions and intron-exon boundaries of BRCA1 and BRCA2 were designed, and optimised. A final set of 94 assays which ran under identical lification conditions were chosen for BRCA1 (36) and BRCA2 (58). Significant attention was placed on primer design to enable reproducible detection of mutations within the licon while minimising unnecessary detection of polymorphisms. Deoxyinosine residues were incorporated into primers that overlay intronic polymorphisms. Multiple 384 well plates were used to facilitate high throughput. 169 BRCA1 and 239 BRCA2 known sequence variants were used to test the licons. We also performed an extensive blinded validation of the protocol with 384 separate patient DNAs. All heterozygous variants were detected with the optimised assays. This is the first HRM approach to screen the entire coding region of the BRCA1 and BRCA2 genes using one set of reaction conditions in a multi plate 384 well format using specifically designed primers. The parallel screening of a relatively large number of s les enables better detection of sequence variants. HRM has the advantages of decreasing the necessary sequencing by more than 90%. This markedly reduced cost of sequencing will result in BRCA1 and BRCA2 mutation testing becoming accessible to in iduals who currently do not undergo mutation testing because of the significant costs involved.
Publisher: Springer New York
Date: 2014
DOI: 10.1007/978-1-4939-0847-9_6
Abstract: Cancer is a complex disease driven by multiple mutations acquired over the lifetime of the cancer cells. These alterations, termed somatic mutations to distinguish them from inherited germline mutations, can include single-nucleotide substitutions, insertions, deletions, copy number alterations, and structural rearrangements. A patient's cancer can contain a combination of these aberrations, and the ability to generate a comprehensive genetic profile should greatly improve patient diagnosis and treatment. Next-generation sequencing has become the tool of choice to uncover multiple cancer mutations from a single tumor source, and the falling costs of this rapid high-throughput technology are encouraging its transition from basic research into a clinical setting. However, the detection of mutations in sequencing data is still an evolving area and cancer genomic data requires some special considerations. This chapter discusses these aspects and gives an overview of current bioinformatics methods for the detection of somatic mutations in cancer sequencing data.
Publisher: Public Library of Science (PLoS)
Date: 10-2020
Publisher: American Association for Cancer Research (AACR)
Date: 04-2023
DOI: 10.1158/1078-0432.C.6533113.V1
Abstract: AbstractPurpose: BRAF V600E mutant metastatic colorectal cancer represents a significant clinical problem, with combination approaches being developed clinically with oral BRAF inhibitors combined with EGFR-targeting antibodies. While compelling preclinical data have highlighted the effectiveness of combination therapy with vemurafenib and small-molecule EGFR inhibitors, gefitinib or erlotinib, in colorectal cancer, this therapeutic strategy has not been investigated in clinical studies. Patients and Methods: We conducted a phase Ib/II dose-escalation/expansion trial investigating the safety/efficacy of the BRAF inhibitor vemurafenib and EGFR inhibitor erlotinib. Results: Thirty-two patients with i BRAF /i V600E positive metastatic colorectal cancer (mCRC) and 7 patients with other cancers were enrolled. No dose-limiting toxicities were observed in escalation, with vemurafenib 960 mg twice daily with erlotinib 150 mg daily selected as the recommended phase II dose. Among 31 evaluable patients with mCRC and 7 with other cancers, overall response rates were 32% [10/31, 16% (5/31) confirmed] and 43% (3/7), respectively, with clinical benefit rates of 65% and 100%. Early ctDNA dynamics were predictive of treatment efficacy, and serial ctDNA monitoring revealed distinct patterns of convergent genomic evolution associated with acquired treatment resistance, with frequent emergence of MAPK pathway alterations, including polyclonal i KRAS /i , i NRAS /i , and i MAP2K1 /i mutations, and i MET /i lification. Conclusions: The Erlotinib and Vemurafenib In Combination Trial study demonstrated a safe and novel combination of two oral inhibitors targeting BRAF and EGFR. The dynamic assessment of serial ctDNA was a useful measure of underlying genomic changes in response to this combination and in understanding potential mechanisms of resistance. /
Publisher: Impact Journals, LLC
Date: 07-09-2016
Publisher: Springer Science and Business Media LLC
Date: 13-12-2013
DOI: 10.1038/SREP03494
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 20-08-2021
Publisher: American Society of Clinical Oncology (ASCO)
Date: 11-0011
DOI: 10.1200/PO.16.00009
Abstract: Circulating tumor DNA (ctDNA) allows noninvasive disease monitoring across a range of malignancies. In metastatic melanoma, the extent to which ctDNA reflects changes in metabolic disease burden assessed by 18 F-labeled fluorodeoxyglucose positron emission tomography (FDG-PET) is unknown. We assessed the role of ctDNA analysis in combination with FDG-PET to monitor tumor burden and genomic heterogeneity throughout treatment. We performed a comprehensive analysis of serial ctDNA and FDG-PET in 52 patients who received systemic therapy for metastatic melanoma. Next-generation sequencing and digital polymerase chain reaction were used to analyze plasma s les from the cohort. ctDNA levels were monitored across patients with mutant BRAF, NRAS, and BRAF/NRAS wild type disease. Mutant BRAF and NRAS ctDNA levels correlated closely with changes in metabolic disease burden throughout treatment. TERT promoter mutant ctDNA levels also paralleled changes in tumor burden, which provide an alternative marker for disease monitoring. Of note, subcutaneous and cerebral disease sites were not well represented in plasma. Early changes in ctDNA and metabolic disease burden were important indicators of treatment response. Patients with an early decrease in ctDNA post-treatment had improved progression-free survival compared with patients in whom ctDNA levels remained unchanged or increased over time (hazard ratio, 2.6 P = .05). ctDNA analysis contributed key molecular information through the identification of putative resistance mechanisms to targeted therapy. A detailed comparison of the genomic architecture of plasma and multiregional tumor biopsy specimens at autopsy revealed the ability of ctDNA to comprehensively capture genomic heterogeneity across multiple disease sites. The findings highlight the powerful role of ctDNA in metastatic melanoma as a complementary modality to functional imaging that allows real-time monitoring of both tumor burden and genomic changes throughout therapy.
Publisher: Society of Nuclear Medicine
Date: 27-04-2017
Publisher: Cold Spring Harbor Laboratory
Date: 23-11-2018
DOI: 10.1101/475947
Abstract: Targeted deep sequencing is a highly effective technology to identify known and novel single nucleotide variants (SNVs) with many applications in translational medicine, disease monitoring and cancer profiling. However, identification of SNVs using deep sequencing data is a challenging computational problem as different sequencing artifacts limit the analytical sensitivity of SNV detection, especially at low variant allele frequencies (VAFs). To address the problem of relatively high noise levels in licon-based deep sequencing data (e.g. with the Ion AmpliSeq technology) in the context of SNV calling, we have developed a new bioinformatics tool called AmpliSolve. AmpliSolve uses a set of normal s les to model position-specific, strand-specific and nucleotide-specific background artifacts (noise), and deploys a Poisson model-based statistical framework for SNV detection. Our tests on both synthetic and real data indicate that AmpliSolve achieves a good trade-off between precision and sensitivity, even at VAF below 5% and as low as 1%. We further validate AmpliSolve by applying it to the detection of SNVs in 96 circulating tumor DNA s les at three clinically relevant genomic positions and compare the results to digital droplet PCR experiments. AmpliSolve is a new tool for in-silico estimation of background noise and for detection of low frequency SNVs in targeted deep sequencing data. Although AmpliSolve has been specifically designed for and tested on licon-based libraries sequenced with the Ion Torrent platform it can, in principle, be applied to other sequencing platforms as well. AmpliSolve is freely available at kleftogi/AmpliSolve .
Publisher: Springer New York
Date: 2019
DOI: 10.1007/978-1-4939-9004-7_9
Abstract: Structural gene fusion rearrangements leading to aberrant signaling are frequently detected in many cancer types. Gene fusions have significant prognostic and predictive value and are screened as part of molecular pathology testing for patient management. Many bioinformatic approaches have been developed to detect fusion mutations including whole-genome sequencing, targeted-based hybridization capture, and transcriptome-based approaches. Here we describe the most commonly used experimental methods to sequence and identify gene fusions using either DNA or RNA. We contrast experimental approaches both in the research and diagnostic setting and describe typical bioinformatic pipelines and software packages used to identify fusions.
Publisher: Oxford University Press (OUP)
Date: 09-2021
DOI: 10.1093/BIOINFORMATICS/BTAB606
Abstract: This work describes two novel workflows for variant calling that extend the widely used algorithms of Strelka2 and FreeBayes to call somatic mutations from multiple related tumour s les and one matched normal s le. We show that these workflows offer higher precision and recall than their single tumour-normal pair equivalents in both simulated and clinical sequencing data. Source code freely available at the following link: atlassian.petermac.org.au/bitbucket rojects/DAW/repos/multis levariantcalling and executable through Janis (github.com/PMCC-BioinformaticsCore/janis) under the GPLv3 licence. Supplementary data are available at Bioinformatics online.
Publisher: American Association for Cancer Research (AACR)
Date: 14-12-2014
DOI: 10.1158/1078-0432.CCR-14-1292
Abstract: Purpose: Low-grade serous ovarian carcinomas (LGSC) are Ras pathway-mutated, TP53 wild-type, and frequently associated with borderline tumors. Patients with LGSCs respond poorly to platinum-based chemotherapy and may benefit from pathway-targeted agents. High-grade serous carcinomas (HGSC) are TP53-mutated and are thought to be rarely associated with borderline tumors. We sought to determine whether borderline histology associated with grade 2 or 3 carcinoma was an indicator of Ras mutation, and we explored the molecular relationship between coexisting invasive and borderline histologies. Experimental Design: We reviewed & ,200 patients and identified 102 serous carcinomas with adjacent borderline regions for analyses, including candidate mutation screening, copy number, and gene expression profiling. Results: We found a similar frequency of low, moderate, and high-grade carcinomas with coexisting borderline histology. BRAF/KRAS alterations were common in LGSC however, we also found recurrent NRAS mutations. Whereas borderline tumors harbored BRAF/KRAS mutations, NRAS mutations were restricted to carcinomas, representing the first ex le of a Ras oncogene with an obligatory association with invasive serous cancer. Coexisting borderline and invasive components showed nearly identical genomic profiles. Grade 2 cases with coexisting borderline included tumors with molecular features of LGSC, whereas others were typical of HGSC. However, all grade 3 carcinomas with coexisting borderline histology were molecularly indistinguishable from typical HGSC. Conclusion: Our findings suggest that NRAS is an oncogenic driver in serous ovarian tumors. We demonstrate that borderline histology is an unreliable predictor of Ras pathway aberration and underscore an important role for molecular classification in identifying patients that may benefit from targeted agents. Clin Cancer Res 20(24) 6618–30. ©2014 AACR.
Publisher: American Society of Clinical Oncology (ASCO)
Date: 10-11-2012
Publisher: Springer Science and Business Media LLC
Date: 19-11-2018
DOI: 10.1038/S41591-018-0243-Z
Abstract: Ibrutinib plus venetoclax is a highly effective combination in mantle cell lymphoma. However, strategies to enable the evaluation of therapeutic response are required. Our prospective analyses of patients within the AIM study revealed genomic profiles that clearly dichotomized responders and nonresponders. Mutations in ATM were present in most patients who achieved a complete response, while chromosome 9p21.1-p24.3 loss and/or mutations in components of the SWI-SNF chromatin-remodeling complex were present in all patients with primary resistance and two-thirds of patients with relapsed disease. Circulating tumor DNA analysis revealed that these alterations could be dynamically monitored, providing concurrent information on treatment response and tumor evolution. Functional modeling demonstrated that compromise of the SWI-SNF complex facilitated transcriptional upregulation of BCL2L1 (Bcl-xL) providing a selective advantage against ibrutinib plus venetoclax. Together these data highlight important insights into the molecular basis of therapeutic response and provide a model for real-time assessment of innovative targeted therapies.
Publisher: American Association for Cancer Research (AACR)
Date: 04-2023
DOI: 10.1158/1078-0432.C.6533113
Abstract: AbstractPurpose: BRAF V600E mutant metastatic colorectal cancer represents a significant clinical problem, with combination approaches being developed clinically with oral BRAF inhibitors combined with EGFR-targeting antibodies. While compelling preclinical data have highlighted the effectiveness of combination therapy with vemurafenib and small-molecule EGFR inhibitors, gefitinib or erlotinib, in colorectal cancer, this therapeutic strategy has not been investigated in clinical studies. Patients and Methods: We conducted a phase Ib/II dose-escalation/expansion trial investigating the safety/efficacy of the BRAF inhibitor vemurafenib and EGFR inhibitor erlotinib. Results: Thirty-two patients with i BRAF /i V600E positive metastatic colorectal cancer (mCRC) and 7 patients with other cancers were enrolled. No dose-limiting toxicities were observed in escalation, with vemurafenib 960 mg twice daily with erlotinib 150 mg daily selected as the recommended phase II dose. Among 31 evaluable patients with mCRC and 7 with other cancers, overall response rates were 32% [10/31, 16% (5/31) confirmed] and 43% (3/7), respectively, with clinical benefit rates of 65% and 100%. Early ctDNA dynamics were predictive of treatment efficacy, and serial ctDNA monitoring revealed distinct patterns of convergent genomic evolution associated with acquired treatment resistance, with frequent emergence of MAPK pathway alterations, including polyclonal i KRAS /i , i NRAS /i , and i MAP2K1 /i mutations, and i MET /i lification. Conclusions: The Erlotinib and Vemurafenib In Combination Trial study demonstrated a safe and novel combination of two oral inhibitors targeting BRAF and EGFR. The dynamic assessment of serial ctDNA was a useful measure of underlying genomic changes in response to this combination and in understanding potential mechanisms of resistance. /
Publisher: American Association for Cancer Research (AACR)
Date: 09-2013
DOI: 10.1158/1078-0432.CCR-13-0398
Abstract: Purpose: The mutation load in melanoma is generally high compared with other tumor types due to extensive UV damage. Translation of exome sequencing data into clinically relevant information is therefore challenging. This study sought to characterize mutations identified in primary cutaneous melanomas and correlate these with clinicopathologic features. Experimental Design: DNA was extracted from 34 fresh-frozen primary cutaneous melanomas and matched peripheral blood. Tumor histopathology was reviewed by two dermatopathologists. Exome sequencing was conducted and mutation rates were correlated with age, sex, tumor site, and histopathologic variables. Differences in mutations between categories of solar elastosis, pigmentation, and BRAF/NRAS mutational status were investigated. Results: The average mutation rate was 12 per megabase, similar to published results in metastases. The average mutation rate in severely sun damaged (SSD) skin was 21 per Mb compared with 3.8 per Mb in non-SSD skin (P = 0.001). BRAF/NRAS wild-type (WT) tumors had a higher average mutation rate compared with BRAF/NRAS–mutant tumors (27 vs. 5.6 mutations per Mb P = 0.0001). Tandem CC& TT/GG& AA mutations comprised 70% of all dinucleotide substitutions and were more common in tumors arising in SSD skin (P = 0.0008) and in BRAF/NRAS WT tumors (P = 0.0007). Targetable and potentially targetable mutations in WT tumors, including NF1, KIT, and NOTCH1, were spread over various signaling pathways. Conclusion: Melanomas arising in SSD skin have higher mutation loads and contain a spectrum of molecular subtypes compared with BRAF- and NRAS-mutant tumors indicating multigene screening approaches and combination therapies may be required for management of these patients. Clin Cancer Res 19(17) 4589–98. ©2013 AACR.
Publisher: Wiley
Date: 30-01-2014
DOI: 10.1002/IJC.28727
Abstract: CDKN2A (p16) disruption is reported as a frequent event in head and neck squamous cell carcinomas that confers poor prognosis. We investigated the frequency of different potential mechanisms of CDKN2A inactivation in oral tongue squamous cell carcinomas (OTSCC) and their impact on patient outcome. From a cohort of 153 OTSCC patients, 131 formalin fixed paraffin embedded blocks of pre-treatment primary tumours were suitable for further molecular analysis. We assessed CDKN2A (p16) levels by immunohistochemistry (IHC), promoter methylation status by methylation-sensitive high resolution melting, mutation status by Sanger sequencing, gene copy number variation by fluorescence in situ hybridisation, and correlated these with patient outcome. We found that the majority of OTSCC did not overexpress p16 (110/116, 95%), assessed by IHC. The frequency of CDKN2A mutations was 20% (21/103), homozygous loss was 7% (7/97), hemizygous loss 31% (30/97), and promoter methylation was 18% (20/113). We found no evidence of these mechanisms in 24/106 (23%) p16 IHC negative tumours. No significant correlation was identified between any potential mechanism of CDKN2A inactivation and clinical features, including smoking status and age. There was a non-significant trend for worse overall survival for p16 IHC negative patients versus positive patients (HR = 1.81, 95% CI = 0.44-7.47, p = 0.40). No relationship was found between mechanisms of CDKN2A disruption and patient outcome. In conclusion, we demonstrate that CDKN2A alteration is a frequent event in OTSCC tumourigenesis. However, no correlation was identified between different potential mechanisms of CDKN2A disruption and clinical characteristics or patient outcome.
Publisher: Elsevier BV
Date: 10-2019
Publisher: Elsevier BV
Date: 05-2019
Publisher: American Society for Clinical Investigation
Date: 09-03-2020
DOI: 10.1172/JCI130887
Publisher: Elsevier BV
Date: 11-2023
Publisher: Oxford University Press (OUP)
Date: 04-2018
Publisher: Springer Science and Business Media LLC
Date: 29-06-2020
Publisher: Springer Science and Business Media LLC
Date: 23-06-2021
DOI: 10.1186/S13059-021-02401-3
Abstract: The human microbiome plays an important role in cancer. Accumulating evidence indicates that commensal microbiome-derived DNA may be represented in minute quantities in the cell-free DNA of human blood and could possibly be harnessed as a new cancer biomarker. However, there has been limited use of rigorous experimental controls to account for contamination, which invariably affects low-biomass microbiome studies. We apply a combination of 16S-rRNA-gene sequencing and droplet digital PCR to determine if the specific detection of cell-free microbial DNA (cfmDNA) is possible in metastatic melanoma patients. Compared to matched stool and saliva s les, the absolute concentration of cfmDNA is low but significantly above the levels detected from negative controls. The microbial community of plasma is strongly influenced by laboratory and reagent contaminants introduced during the DNA extraction and sequencing processes. Through the application of an in silico decontamination strategy including the filtering of licon sequence variants (ASVs) with batch dependent abundances and those with a higher prevalence in negative controls, we identify known gut commensal bacteria, such as Faecalibacterium , Bacteroides and Ruminococcus , and also other uncharacterised ASVs. We analyse additional plasma s les, highlighting the potential of this framework to identify differences in cfmDNA between healthy and cancer patients. Together, these observations indicate that plasma can harbour a low yet detectable level of cfmDNA. The results highlight the importance of accounting for contamination and provide an analytical decontamination framework to allow the accurate detection of cfmDNA for future biomarker studies in cancer and other diseases.
Publisher: Ferrata Storti Foundation (Haematologica)
Date: 12-2011
No related grants have been discovered for Stephen Q. Wong.