Oxford University researchers have located two genetic faults which increase the risk of individuals with a history of bowel cancer in the family developing it themselves.
The research was carried out by the Wellcome Trust Centre for Human Genetics in Oxford and Cancer Research UK, and established a high correlation between bowel cancer development and mutations in two specific genes, POLE and POLD1, which are involved in the DNA repairing processes.
The research found that defects in these genes can cause an accumulation of DNA damage in the body that may contribute to bowel cancer.
The Cancer Research UK-funded project selected twenty people as study subjects, eight of which had previously been diagnosed with bowel cancer whilst the rest had a first-degree relative who developed the illness. After sequencing the genomes of the 20 participants, the scientists found both of the faulty genes in all subjects with bowel cancer or malignant tumours in the bowel.
To further consolidate the result, the research team broadened their inspection base to 4000 people with bowel cancer and a control group of 6700 without the disease. Not a single case of genetic deficiencies in POLE or POLD1 was found in the control group, while the researchers found 12 people with POLE fault and one person with POLD1 fault in the bowel cancer group.
However, Oxford Professor Ian Tomlinson who led the study pointed out: “There are some families where large numbers of relatives develop bowel cancer but who don’t have any of the known gene faults that raise the risk of developing the disease.”
Professor Richard Houlston from The Institute of Cancer Research, a co-leader of the research commented, “Uncovering gene faults like these two is extremely important, as inherited susceptibility plays a role in the development of about a third of all cases of colorectal cancer. This is one of the most important discoveries in bowel cancer genetics in years.”
“It should allow us to manage families affected by inherited bowel cancer much more effectively, and it offers new clues for the prevention or treatment of all forms of the disease,” he added.
According to NHS, bowel cancer, or more formally known as colorectal cancer (CRC), is the second most common type of cancer among women in the UK, second after breast cancer. It is the third most common cancer among men behind prostate and lung cancer.
Currently under NHS, everyone between the ages of 60 and 69 is offered bowel cancer screening every two years. Almost three quarters of the people affected are over 65.
Like many other cancers, early diagnosis is crucial in the treatment of bowel cancer. The survival rate five years after detection of the cancer is about 90% if found in early stages, compared to the 6% in the most advanced stage. The average chance of surviving five years after diagnosis of bowel cancer is approximately 50%.
