ORCID Profile
0000-0001-9100-1807
Current Organisation
The University of Sydney Sydney University Press
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Publisher: Impact Journals, LLC
Date: 30-11-2018
Publisher: Springer Science and Business Media LLC
Date: 04-06-2019
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-2017
Publisher: Wiley
Date: 15-05-2019
DOI: 10.1002/PROS.23823
Abstract: The androgen‐regulated gene TMPRSS2 to the ETS transcription factor gene ERG fusion is the most common genomic alteration acquired during prostate tumorigenesis and biased toward men of European ancestry. In contrast, African American men present with more advanced disease, yet their tumors are less likely to acquire TMPRSS2‐ERG . Data for Africa is scarce. RNA was made available for genomic analyses from 181 prostate tissue biopsy cores from Black South African men, 94 with and 87 without pathological evidence for prostate cancer. Reverse transcription polymerase chain reaction was used to screen for the TMPRSS2‐ERG fusion, while transcript junction coordinates and isoform frequencies, including novel gene fusions, were determined using targeted RNA sequencing. Here we report a frequency of 13% for TMPRSS2‐ERG in tumors from Black South Africans. Present in 12/94 positive versus 1/87 cancer negative prostate tissue cores, this suggests a 92.62% predictivity for a positive cancer diagnosis ( P = 0.0031). At a frequency of almost half that reported for African Americans and roughly a quarter of that reported for men of European ancestry, acquisition of TMPRSS2‐ERG appears to be inversely associated with aggressive prostate cancer. Further support was provided by linking the presence of TMPRSS2‐ERG to low‐grade disease in younger patients ( P = 0.0466), with higher expressing distal ERG fusion junction coordinates. Only the second study of its kind for the African continent, we support a link between TMPRSS2‐ERG status and prostate cancer racial health disparity beyond the borders of the United States. We call for urgent evaluation of androgen deprivation therapy within Africa.
Publisher: Elsevier BV
Date: 02-2017
Publisher: MDPI AG
Date: 07-05-2020
Abstract: Background: While critical insights have been gained from evaluating the genomic landscape of metastatic prostate cancer, utilizing this information to inform personalized treatment is in its infancy. We performed a retrospective pilot study to assess the current impact of precision medicine for locally advanced and metastatic prostate adenocarcinoma and evaluate how genomic data could be harnessed to in idualize treatment. Methods: Deep whole genome-sequencing was performed on 16 tumour-blood pairs from 13 prostate cancer patients whole genome optical mapping was performed in a subset of 9 patients to further identify large structural variants. Tumour s les were derived from prostate, lymph nodes, bone and brain. Results: Most s les had acquired genomic alterations in multiple therapeutically relevant pathways, including DNA damage response (11/13 cases), PI3K (7/13), MAPK (10/13) and Wnt (9/13). Five patients had somatic copy number losses in genes that may indicate sensitivity to immunotherapy (LRP1B, CDK12, MLH1) and one patient had germline and somatic BRCA2 alterations. Conclusions: Most cases, whether primary or metastatic, harboured therapeutically relevant alterations, including those associated with PARP inhibitor sensitivity, immunotherapy sensitivity and resistance to androgen pathway targeting agents. The observed intra-patient heterogeneity and presence of genomic alterations in multiple growth pathways in in idual cases suggests that a precision medicine model in prostate cancer needs to simultaneously incorporate multiple pathway-targeting agents. Our whole genome approach allowed for structural variant assessment in addition to the ability to rapidly reassess an in idual’s molecular landscape as knowledge of relevant biomarkers evolve. This retrospective oncological assessment highlights the genomic complexity of prostate cancer and the potential impact of assessing genomic data for an in idual at any stage of the disease.
Publisher: Research Square Platform LLC
Date: 09-06-2023
DOI: 10.21203/RS.3.RS-2993516/V1
Abstract: African ancestry is a significant risk factor for prostate cancer and advanced disease. Yet, genetic studies have largely been conducted outside the context of Sub-Saharan Africa, identifying 278 common risk variants contributing to a multiethnic polygenic risk score, with rare variants focused on a panel of roughly 20 pathogenic genes. Based on this knowledge, we were unable to determine polygenic risk or differentiate prostate cancer status interrogating whole genome data for 113 Black South African men. To further assess for potentially functional common and rare variant associations, we interrogated 247,780 exomic variants for 798 Black South African men using a case versus control or aggressive versus non-aggressive study design. Notable genes of interest included HCP5 , RFX6 and H3C1 for risk, and MKI67 and KLF5 for aggressive disease. Our study highlights the need for further inclusion across the African diaspora to establish African-relevant risk models aimed at reducing prostate cancer health disparities.
Publisher: Public Library of Science (PLoS)
Date: 11-12-2014
Publisher: Impact Journals, LLC
Date: 05-10-2016
Publisher: American Society for Microbiology
Date: 10-2009
DOI: 10.1128/JVI.00668-09
Abstract: Knowledge of endogenous retroviruses (ERVs) in crocodilians (Crocodylia) is limited, and their distribution among extant species is unclear. Here we analyzed the phylogenetic relationships of these retroelements in 20 species of crocodilians by studying the pro-pol gene. The results showed that crocodilian ERVs (CERVs) cluster into two major clades (CERV 1 and CERV 2). CERV 1 clustered as a sister group of the genus Gammaretrovirus , while CERV 2 clustered distantly with respect to all known ERVs. Interestingly, CERV 1 was found only in crocodiles (Crocodylidae). The data generated here could assist future studies aimed at identifying orthologous and paralogous ERVs among crocodilians.
Publisher: Wiley
Date: 14-11-2018
DOI: 10.1002/PROS.23440
Abstract: Mitochondrial genome (mtDNA) content is depleted in many cancers. In prostate cancer, there is intra-glandular as well as inter-patient mtDNA copy number variation. In this study, we determine if mtDNA content can be used as a predictor for prostate cancer staging and outcomes. Fresh prostate cancer biopsies from 115 patients were obtained at time of surgery. All cores underwent pathological review, followed by isolation of cancer and normal tissue. DNA was extracted and qPCR performed to quantify the total amount of mtDNA as a ratio to genomic DNA. Differences in mtDNA content were compared for prostate cancer pathology features and disease outcomes. We showed a significantly reduced mtDNA content in prostate cancer compared with normal adjacent prostate tissue (mean difference 1.73-fold, P-value <0.001). Prostate cancer with increased mtDNA content showed unfavorable pathologic characteristics including, higher disease stage (PT2 vs PT3 P-value = 0.018), extracapsular extension (P-value = 0.02) and a trend toward an increased Gleason score (P-value = 0.064). No significant association was observed between changes in mtDNA content and biochemical recurrence (median follow up of 107 months). Contrary to other cancer types, prostate cancer tissue shows no universally depleted mtDNA content. Rather, the change in mtDNA content is highly variable, mirroring known prostate cancer genome heterogeneity. Patients with high mtDNA content have an unfavorable pathology, while a high mtDNA content in normal adjacent prostate tissue is associated with worse prognosis.
Publisher: Public Library of Science (PLoS)
Date: 04-02-2014
Publisher: Impact Journals, LLC
Date: 03-2017
Publisher: American Association for Cancer Research (AACR)
Date: 13-12-2018
DOI: 10.1158/0008-5472.CAN-18-0254
Abstract: The first whole-genome sequencing study for high-risk prostate cancer in African men allows a simultaneous comparison of ethnic differences relative to European populations and of the influences of the environment relative to African-American men.
Publisher: Wiley
Date: 2023
DOI: 10.1002/CTM2.1142
Publisher: Springer Science and Business Media LLC
Date: 25-09-2023
Publisher: MDPI AG
Date: 03-11-2023
DOI: 10.20944/PREPRINTS202305.1875.V1
Abstract: Prostate cancer is driven by acquired genetic alterations, including those impacting the epigenetic machinery. With African ancestry a significant risk factor for aggressive disease, we hypothesize that dysregulation among the roughly 656 epigenetic genes may contribute to prostate cancer health disparities. Interrogating prostate tumor genomic data from 109 men of southern African and 56 men of European Australian ancestry, we found African-derived tumors to present with a longer tail of epigenetic driver gene candidates (72 versus 10). Biased towards African-specific drivers (63 versus 9 shared), many are novel to prostate cancer (18/63) including several putative therapeutic targets (CHD7, DPF3, POLR1B, SETD1B, UBTF and VPS72). Through clustering of all variant types and copy number alterations, we describe two epigenetic PCa taxonomies capable of differentiating patients by ancestry and predicted clinical outcomes. We identified top genes in African and European-derived tumors that represent a multifunctional “generic machinery”, alteration to which may be instrumental in epigenetic dysregulation and prostate tumorigenesis. In conclusion, numerous somatic alterations in the epigenetic machinery drive prostate carcinogenesis but African-derived tumors appear to achieve this with greater ersity amongst such alterations. The greater novelty observed in African-derived tumors illustrates the significant clinical benefit to be derived from a much needed African tailored approach to prostate cancer healthcare aimed at reducing prostate cancer health disparities.
Publisher: Springer Science and Business Media LLC
Date: 05-08-2012
DOI: 10.1007/S00251-012-0637-X
Abstract: Saltwater crocodiles are in high demand for the production of luxury fashion items. However, their susceptibility to disease incurs substantial losses and it is hoped to be able to genetically select these animals for disease resistance. So far, this has only been enabled by phenotypic selection. Investigating the major histocompatibility complex (MHC) could provide insight into the ability of an in idual to respond to pathogens acting as a selective pressure on the host. Here, we assessed genetic ersity and a role of selection in shaping the ersity of MHC class I exon 3 among 42 saltwater crocodiles from nine river basins in the Northern Territory, Australia. We generated 640 sequences using cloning and sequencing methods and identified 43 MHC variants among them. Phylogenetic analyses clustered these variants into two major clades, which may suggest two gene lineages. We found the number of variants within an in idual varying between one and seven, indicating that there are at least four gene loci in this species. Selection detection analyses revealed an elevated ratio of nonsynonymous to synonymous substitutions (mean = 1.152 per codon), suggesting balancing selection. Population differentiation analyses revealed that the MHC did not show structuring among the river basins, and there were some shared variants among them. This may be a result of possible gene flow and/or similar selection pressures among populations. These findings provide background knowledge to identify potential MHC markers, which could be used for selecting genetically variable in iduals for future disease associations. All MHC class I exon 3 sequences reported in this paper were submitted to the GenBank database with following accession numbers: HQ008785-HQ008789, HQ008791-HQ008798, HQ008808-HQ008815, HQ008824, HQ008826-HQ008830, HQ008835, HQ008839, HQ008842-HQ008850, and JX023536-JX023540.
Publisher: Springer Science and Business Media LLC
Date: 02-04-2014
DOI: 10.1038/HDY.2014.30
Publisher: Springer Science and Business Media LLC
Date: 12-2019
DOI: 10.1186/S13072-019-0321-6
Abstract: Current array-based methods for the measurement of DNA methylation rely on the process of sodium bisulfite conversion to differentiate between methylated and unmethylated cytosine bases in DNA. In the absence of genotype data this process can lead to ambiguity in data interpretation when a s le has polymorphisms at a methylation probe site. A common way to minimize this problem is to exclude such potentially problematic sites, with some methods removing as much as 60% of array probes from consideration before data analysis. Here, we present an algorithm implemented in an R Bioconductor package, MethylToSNP, which detects a characteristic data pattern to infer sites likely to be confounded by polymorphisms. Additionally, the tool provides a stringent reliability score to allow thresholding on SNP predictions. We calibrated parameters and thresholds used by the algorithm on simulated and real methylation data sets. We illustrate findings using methylation data from YRI (Yoruba in Ibadan, Nigeria), CEPH (European descent) and KhoeSan (southern African) populations. Our polymorphism predictions made using MethylToSNP have been validated through SNP databases and bisulfite and genomic sequencing. The benefits of this method are threefold. First, it prevents extensive data loss by considering only SNPs specific to the in iduals in the study. Second, it offers the possibility to identify new polymorphisms in s les for which there is little known about the genetic landscape. Third, it identifies variants as they exist in functional regions of a genome, such as in CTCF (transcriptional repressor) sites and enhancers, that may be common alleles or personal mutations with potential to deleteriously affect genomic regulatory activities. We demonstrate that MethylToSNP is applicable to the Illumina 450K and Illumina 850K EPIC array data and is also backwards compatible to the 27K methylation arrays. Going forward, this kind of nuanced approach can increase the amount of information derived from precious data sets by considering s les of the project in idually to enable more informed decisions about data cleaning.
Publisher: Wiley
Date: 27-08-2019
DOI: 10.1002/PROS.23897
Abstract: Inflammation is a hallmark of prostate cancer (PCa), yet no pathogenic agent has been identified. Men from Africa are at increased risk for both aggressive prostate disease and infection. We hypothesize that pathogenic microbes may be contributing, at least in part, to high‐risk PCa presentation within Africa and in turn the observed ethnic disparity. Here we reveal through metagenomic analysis of host‐derived whole‐genome sequencing data, the microbial content within prostate tumor tissue from 22 men. What is unique about this study is that patients were separated by ethnicity, African vs European, and environments, Africa vs Australia. We identified 23 common bacterial genera between the African, Australian, and Chinese prostate tumor s les, while nonbacterial microbes were notably absent. While the most abundant genera across all s les included: Escherichia , Propionibacterium , and Pseudomonas , the core prostate tumor microbiota was enriched for Proteobacteria . We observed a significant increase in the richness of the bacterial communities within the African vs Australian s les ( t = 4.6‐5.5 P = .0004‐.001), largely driven by eight predominant genera. Considering core human gut microbiota, African prostate tissue s les appear enriched for Escherichia and Acidovorax , with an abundance of Eubacterium associated with host tumor hypermutation. Our study provides suggestive evidence for the presence of a core, bacteria‐rich, prostate microbiome. While unable to exclude for fecal contamination, the observed increased bacterial content and richness within the African vs non‐African s les, together with elevated tumor mutational burden, suggests the possibility that bacterially‐driven oncogenic transformation within the prostate microenvironment may be contributing to aggressive disease presentation in Africa.
Publisher: Springer Science and Business Media LLC
Date: 20-11-2013
DOI: 10.1007/S00251-013-0746-1
Abstract: The major histocompatibility complex (MHC) is a dynamic genomic region with an essential role in the adaptive immunity of jawed vertebrates. The evolution of the MHC has been dominated by gene duplication and gene loss, commonly known as the birth-and-death process. Evolutionary studies of the MHC have mostly focused on model species. However, the investigation of this region in non-avian reptiles is still in its infancy. To provide insights into the evolutionary mechanisms that have shaped the ersity of this region in the Order Crocodylia, we investigated MHC class I exon 3, intron 3, and exon 4 across 20 species of the families Alligatoridae and Crocodilidae. We generated 124 DNA sequences and identified 31 putative functional variants as well as 14 null variants. Phylogenetic analyses revealed three gene groups, all of which were present in Crocodilidae but only one in Alligatoridae. Within these groups, variants generally appear to cluster at the genus or family level rather than in species-specific groups. In addition, we found variation in gene copy number and some indication of interlocus recombination. These results suggest that MHC class I in Crocodylia underwent independent events of gene duplication, particularly in Crocodilidae. These findings enhance our understanding of MHC class I evolution and provide a preliminary framework for comparative studies of other non-avian reptiles as well as ersity assessment within Crocodylia.
Publisher: Springer Science and Business Media LLC
Date: 31-08-2022
DOI: 10.1038/S41586-022-05154-6
Abstract: Prostate cancer is characterized by considerable geo-ethnic disparity. African ancestry is a significant risk factor, with mortality rates across sub-Saharan Africa of 2.7-fold higher than global averages 1 . The contributing genetic and non-genetic factors, and associated mutational processes, are unknown 2,3 . Here, through whole-genome sequencing of treatment-naive prostate cancer s les from 183 ancestrally (African versus European) and globally distinct patients, we generate a large cancer genomics resource for sub-Saharan Africa, identifying around 2 million somatic variants. Significant African-ancestry-specific findings include an elevated tumour mutational burden, increased percentage of genome alteration, a greater number of predicted damaging mutations and a higher total of mutational signatures, and the driver genes NCOA2 , STK19 , DDX11L1 , PCAT1 and SETBP1 . Examining all somatic mutational types, we describe a molecular taxonomy for prostate cancer differentiated by ancestry and defined as global mutational subtypes (GMS). By further including Chinese Asian data, we confirm that GMS-B (copy-number gain) and GMS-D (mutationally noisy) are specific to African populations, GMS-A (mutationally quiet) is universal (all ethnicities) and the African–European-restricted subtype GMS-C (copy-number losses) predicts poor clinical outcomes. In addition to the clinical benefit of including in iduals of African ancestry, our GMS subtypes reveal different evolutionary trajectories and mutational processes suggesting that both common genetic and environmental factors contribute to the disparity between ethnicities. Analogous to gene–environment interaction—defined here as a different effect of an environmental surrounding in people with different ancestries or vice versa—we anticipate that GMS subtypes act as a proxy for intrinsic and extrinsic mutational processes in cancers, promoting global inclusion in landmark studies.
Publisher: Oxford University Press (OUP)
Date: 20-11-2019
DOI: 10.1634/THEONCOLOGIST.2019-0590
Abstract: Current literature is inconsistent in the associations between computed tomography (CT)-based body composition measures and adverse outcomes in older patients with colorectal cancer (CRC). Moreover, the associations with consecutive treatment modalities have not been studied. This study compared the associations of CT-based body composition measures with surgery- and chemotherapy-related complications and survival in older patients with CRC. A retrospective single-center cohort study was conducted in patients with CRC aged ≥65 years who underwent elective surgery between 2010 and 2014. Gender-specific standardized scores of preoperative CT-based skeletal muscle (SM), muscle density, intermuscular adipose tissue (IMAT), visceral adipose tissue (VAT), subcutaneous adipose tissue, IMAT percentage, SM/VAT, and body mass index (BMI) were tested for their associations with severe postoperative complications, prolonged length of stay (LOS), readmission, and dose-limiting toxicity using logistic regression and 1-year and long-term survival (range 3.7–6.6 years) using Cox regression. Bonferroni correction was applied to account for multiple testing. The study population consisted of 378 patients with CRC with a median age of 73.4 (interquartile range 69.5–78.4) years. Severe postoperative complications occurred in 13.0%, and 39.4% of patients died during follow-up. Dose-limiting toxicity occurred in 77.4% of patients receiving chemotherapy (n = 53). SM, muscle density, VAT, SM/VAT, and BMI were associated with surgery-related complications, and muscle density, IMAT, IMAT percentage, and SM/VAT were associated with long-term survival. After Bonferroni correction, no CT-based body composition measure was significantly associated with adverse outcomes. Higher BMI was associated with prolonged LOS. The associations between CT-based body composition measures and adverse outcomes of consecutive treatment modalities in older patients with CRC were not consistent or statistically significant.
Publisher: MDPI AG
Date: 07-2023
Abstract: Prostate cancer is driven by acquired genetic alterations, including those impacting the epigenetic machinery. With African ancestry as a significant risk factor for aggressive disease, we hypothesize that dysregulation among the roughly 656 epigenetic genes may contribute to prostate cancer health disparities. Investigating prostate tumor genomic data from 109 men of southern African and 56 men of European Australian ancestry, we found that African-derived tumors present with a longer tail of epigenetic driver gene candidates (72 versus 10). Biased towards African-specific drivers (63 versus 9 shared), many are novel to prostate cancer (18/63), including several putative therapeutic targets (CHD7, DPF3, POLR1B, SETD1B, UBTF, and VPS72). Through clustering of all variant types and copy number alterations, we describe two epigenetic PCa taxonomies capable of differentiating patients by ancestry and predicted clinical outcomes. We identified the top genes in African- and European-derived tumors representing a multifunctional “generic machinery”, the alteration of which may be instrumental in epigenetic dysregulation and prostate tumorigenesis. In conclusion, numerous somatic alterations in the epigenetic machinery drive prostate carcinogenesis, but African-derived tumors appear to achieve this state with greater ersity among such alterations. The greater novelty observed in African-derived tumors illustrates the significant clinical benefit to be derived from a much needed African-tailored approach to prostate cancer healthcare aimed at reducing prostate cancer health disparities.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 12-12-2014
Abstract: To provide context for the ersification of archosaurs—the group that includes crocodilians, dinosaurs, and birds—we generated draft genomes of three crocodilians: Alligator mississippiensis (the American alligator), Crocodylus porosus (the saltwater crocodile), and Gavialis gangeticus (the Indian gharial). We observed an exceptionally slow rate of genome evolution within crocodilians at all levels, including nucleotide substitutions, indels, transposable element content and movement, gene family evolution, and chromosomal synteny. When placed within the context of related taxa including birds and turtles, this suggests that the common ancestor of all of these taxa also exhibited slow genome evolution and that the comparatively rapid evolution is derived in birds. The data also provided the opportunity to analyze heterozygosity in crocodilians, which indicates a likely reduction in population size for all three taxa through the Pleistocene. Finally, these data combined with newly published bird genomes allowed us to reconstruct the partial genome of the common ancestor of archosaurs, thereby providing a tool to investigate the genetic starting material of crocodilians, birds, and dinosaurs.
Publisher: Harborside Press, LLC
Date: 03-2023
Abstract: Background: Germline testing for prostate cancer is on the increase, with clinical implications for risk assessment, treatment, and management. Regardless of family history, NCCN recommends germline testing for patients with metastatic, regional, very-high-risk localized, and high-risk localized prostate cancer. Although African ancestry is a significant risk factor for aggressive prostate cancer, due to a lack of available data no testing criteria have been established for ethnic minorities. Patients and Methods: Through deep sequencing, we interrogated the 20 most common germline testing panel genes in 113 Black South African males presenting with largely advanced prostate cancer. Bioinformatic tools were then used to identify the pathogenicity of the variants. Results: After we identified 39 predicted deleterious variants (16 genes), further computational annotation classified 17 variants as potentially oncogenic (12 genes 17.7% of patients). Rare pathogenic variants included CHEK2 Arg95Ter, BRCA2 Trp31Arg, ATM Arg3047Ter (2 patients), and TP53 Arg282Trp. Notable oncogenic variants of unknown pathogenicity included novel BRCA2 Leu3038Ile in a patient with early-onset disease, whereas patients with FANCA Arg504Cys and RAD51C Arg260Gln reported a family history of prostate cancer. Overall, rare pathogenic and early-onset or familial-associated oncogenic variants were identified in 6.9% (5/72) and 9.2% (8/87) of patients presenting with a Gleason score ≥8 or ≥4 + 3 prostate cancer, respectively. Conclusions: In this first-of-its-kind study of southern African males, we provide support of African inclusion for advanced, early-onset, and familial prostate cancer genetic testing, indicating clinical value for 30% of current gene panels. Recognizing current panel limitations highlights an urgent need to establish testing guidelines for men of African ancestry. We provide a rationale for considering lowering the pathologic diagnostic inclusion criteria and call for further genome-wide interrogation to ensure the best possible African-relevant prostate cancer gene panel.
Publisher: Informa UK Limited
Date: 06-09-2020
Publisher: Informa UK Limited
Date: 05-06-2019
No related grants have been discovered for Weerachai Jaratlerdsiri.