US scientists have identified a region of DNA, which may contain a novel gene responsible for the progression and spread of colorectal (bowel) cancer.
The scientists analysed the DNA of 81 people from five generations of a single family with an unusually high incidence of bowel cancer - three individuals had bowel cancer and nine other members and two spouses had polyps. As none of the family members had any of the genetic mistakes which had previously been linked to bowel cancer, the aim of the study was to identify new genetic faults which could be involved.
The researchers found that a stretch of DNA, located on chromosome 13, was significantly associated with the incidence of the disease and with the development of bowel polyps (pre-cancerous growths) among members of one large family.
Although the key gene(s) within the DNA region have not yet been found, the authors concluded that 'identification of the precise gene and causative genetic change will be an important step to understand cancer progression and metastasis.' They also noted that this region of chromosome 13 is often over-activated in up to half of bowel cancer cases, providing further evidence that genes within this area play an important role.
Bowel cancer is the third most common cancer in the UK, and the second leading cause of cancer death in the UK and US. Most cases begin as a small polyp on the inner lining of the bowel which, if left untreated, can grow through the bowel wall and spread to other organs. It is estimated that up to 25 per cent of cases arise due to unknown inherited genetic factors and large families, such as the one studied here, provide valuable information in the search for the important genes.
Henry Scowcroft, information manager for Cancer Research UK, said: 'This finding is a small piece in a bigger jigsaw puzzle, but adds to global research efforts that will ultimately benefit people with bowel cancer'.
The research was conducted by Deborah Neklason and colleagues and published in the Journal of Medical Genetics.
