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Study discovers genetic factors for colorectal cancer

Category: Cancer Detection and Tumor Markers

A recent study published in the journal Nature Genetics has found three genetic "hot spots" that may be responsible for the development of colorectal cancer, which is the third most common kind of cancer in the U.S., according to the American Cancer Society. The study is the first of its kind to look at other demographics than white Europeans.

"Looking at different ethnic groups is important because the genetic structures can be different enough that variants identified in one population do not explain risk in other populations," said study author Wei Zheng, M.D., Ph.D., MPH. "Because of the difference in genetic structures and underlying environment exposures, it might be easier to discover some risk variants in studies conducted in non-European populations."

The study authors used a method known as genome-wide association study to look for genetic variants that could be attributed to the disease. They analyzed 2,098 colorectal cancer cases and 5,749 controls, and found 64 variants that could possibly be linked to the cancer. Zheng, who is also the founder of the Asia Colorectal Cancer Consortium, noted that the findings have important implications for both European and Asian populations. While the functions of these genes are unknown, they may lead to cancer therapies and prevention methods in the future.

Alternative causes
While genetics may play a crucial role in the development of colorectal cancer, the National Institutes of Health (NIH) notes that some other risk factors include being older than 60, eating a diet rich in red meat, having cancer in other parts of the body, having inflammatory bowel disease like Crohn's and ulcerative colitis and having a personal history of breast cancer.

Symptoms and diagnosis
Some symptoms of colorectal, according to the NIH, include abdominal pain, blood in the stool, diarrhea and weight loss for no apparent reason.

In order to diagnose colorectal cancer a physician may first conduct a physical exam during which he or she presses down on the patient's stomach to feel for a lump in the abdomen. A doctor may also issue a fecal occult blood test to look for traces of blood in the stool, which is usually an indicator of the condition. This may also be accompanied by a colonoscopy or a sigmoidoscopy, which is a procedure in which a physician looks inside the colon or the rectum.