After age 80, heredity is a major risk factor for colorectal cancer. Now scientists have a new tool to help them identify people at risk for genetically linked colon or endometrial cancer.
It’s not known exactly why colorectal cancer begins. Some people carry genes that make them unusually susceptible to certain cancers, and some people have genes that are specific for colorectal cancer. In fact, because colon cancer is relatively easy to identify in the precancerous stage, the genes involved in colon cancer were some of the first cancer-related genes to be identified and studied.
Now an article in the Journal of the American Medical Association (Volume 296, pages 1469 and 1479) reports that two independent research teams have developed questionnaires that may help identify the risk of a genetically linked hereditary colon or endometrial cancer.
Lynch syndrome, which represents 2–7% of all colorectal cancers, is due to a mutation on the genes MLH1, MSH2, or MSH6, which usually protect against cancer. It is also known as hereditary nonpolyposis colon cancer (HNPCC) and is connected with endometrial cancer. Genetic testing can confirm the syndrome, but it is expensive and may not be necessary. The written tests can screen for the possibility of Lynch syndrome based on patients’ answers to questions about family and personal health histories, say researchers at Johns Hopkins University, who developed one of the questionnaires. They validated the program, called MMRpro, by testing it on 279 patients’ family histories and then testing their genes.
A similar test based on histories of 1,914 patients was developed at the Brigham and Women’s Hospital in Boston. That program, called PREMM1,2, is a risk assessment for mutations on genes MLH1 and MSH2. The questionnaires are available free on the Internet, but researchers caution that they should be used with the advice of a physician or a genetic or cancer counselor.
