The genetics of inherited and sporadic colorectal cancer
Project Leader: Dr Sarah Briggs, Academic Clinical Fellow
Sarah’s research investigates the genetics of inherited and sporadic colorectal cancer. Much of her project focuses on a cancer syndrome called Polymerase Proofreading-Associated Polyposis (PPAP), recently characterised by colleagues, and the role of the genes implicated, POLE and POLD1, in sporadic tumour development. This condition is caused by mutations in the exonuclease domains of these genes, and has a variable phenotype including early-onset or multiple colorectal cancers, multiple or large colonic polyps, and endometrial cancers.
Sarah and the lab are characterising PPAP by sequencing these genes in their large cohort of individuals with colorectal cancer, endometrial cancer, or multiple colorectal adenomas, to identify further carriers (using a combination of Sanger sequencing, targeted next-generation sequencing, and whole-genome sequencing) and characterising the carriers’ phenotypes. They have also investigated the role of these mutations in sporadic endometrial cancer; they found POLE mutations in 7% of tumours and further work characterised the nature of the mutations and tumours. They are also investigating whether germline mutations might affect the de novo mutation rate using whole-genome sequencing of affected parent-offspring quintets.
In addition Sarah has also been trying to identify and characterise other genes predisposing patients to colorectal cancer, through whole-genome sequencing of patients with early-onset colorectal cancers and multiple adenomas, followed by prioritisation of variants found and further exploration of top candidates.
Sarah presented some of this work at The American Society of Human Genetics Meeting 2014 in San Diego and has so far published three papers, with others pending.