A study by London’s Institute of Cancer Research has identified five genes that appear to cause bowel cancer.
The researchers say their findings could lead to new treatments for the disease, which is the third most common cancer worldwide.
According to a report published in the journal Nature Communications, researchers sequenced all the genes used to produce protein — known as the exome — of 1,000 patients with a family history of bowel cancer who had developed the disease at a young age.
They concluded that there are unlikely to be any further major bowel cancer genes beyond the 17 that have now been found.
Mutations in those genes accounted for between 15 and 30 per cent of the 1,000 cases of inherited bowel cancer. Some of the remaining risk is attributed to common genetic variations that each have a very small effect.
Professor Richard Houlston, the study’s lead author, said: ‘The research closes one chapter in the study of bowel cancer, by concluding that all the major risk genes have now been found.
‘But it opens another by underlining the importance of tracking down the many missing genetic variations which each have a very small effect alone, but together make the biggest impacts on inherited risk.
‘Our study is the largest ever conducted of the genetics of bowel cancer and sets out a detailed map of the diseases that could lead us to new ways of treating or preventing it.’
This lab-based study analysed tumour specimens from bowel cancer samples and mapped their genetic sequence.
A particular sequence was identified (17 genes) that, when viewed in conjunction with mutations for adenomatous polyposis coli, the gene whose mutations usually precede the majority of colorectal cancer, is likely to pave the way for better prognosis. The staging of the disease — that is, how the severity of the cancer is determined — can now potentially be refined at the genetic level.
Cancer is staged both to allow selection of treatment but also to inform prognosis and, in the case of colorectal cancer, it is traditionally performed at surgery. With more information gleaned at the molecular level, patients can be better informed regarding their prognosis to a more precise degree.
The trend in cancer research is individualised cancer therapy as opposed to the shot-gun approach traditionally used. This paper is valuable as it will contribute greatly to this, particularly if the findings are replicated.
Research score: 4/5