Normally cells only divide when they receive a stimulus from a hormone or growth factor. The PI3-kinase pathway responds to these stimuli and has been implicated in cellular immunity as well as cancer which occurs when cells divide uncontrollably and invade surrounding tissues. We have identified a putative oncogene (cancer causing gene) called MTMR4 that appears to regulate cell growth-invasion and pathogen invasion of immune cells. We aim to characterise the role of MTMR4 in these systems.