Obesity has long been thought to increase the risk for heart disease and cancer in general. Breast cancer patients appear to have low chances of survival previous studies have shown. Now, researchers have found a genetic link between obesity and colon cancer, which might lead to more effective screening tests for the disease.

Dr. Boris Pasche, lead researcher and director of the division of hematology and oncology at the UAB Comprehensive Cancer Center said adiponectin, also called ADIPOQ, a hormone secreted by the adipose tissue has been linked with colorectal cancer.

Overweight people who have a greater risk of cancer typically have less of the hormone, while those people with more, have less risk of diabetes and heart disease.

For the study, Pasche analyzed adiponectin genes from about 1,100 people of Ashkenazi Jewish ancestry, including 441 patients suffering from colon cancer. This population is known to be at high risk of colon cancer. Three adiponectin gene variants, and one adiponectin receptor gene variant, affected colon cancer risk.

Further, the researchers analyzed the same gene variants in 199-colon cancer patients and 199 matched controls in mixed-ethnicity Chicago-area residents. Only one variant of the adiponectin gene was linked to colon cancer.

When combining the findings of the studies, the researchers found that people who inherit a common variant of the gene have up to a 30 percent lower risk of colon cancer compared with people without this gene variant.

This is the first time when researchers find an association between genetic variants of the fat hormone and colorectal cancer, Pasche said.

“Our hope is that we can significantly improve the screening and early detection for this disease, and open new avenues for better understanding the genetic and lifestyle factors that influence colon cancer risk, he added.

Colon cancer is the second leading cause of cancer deaths in the United States and the third most common type of cancer. Colorectal cancer claims about 56,000 lives every year. The American Cancer Society estimates almost 150,000 new cases of colorectal cancer for 2008 in the U.S. Screening for polyps is recommended at age 50, but people avoid standard procedures because they are unpleasant.

They involve inserting a long and flexible tube in a patient’s large intestine (rectum and colon). A small video camera is attached to the colonoscope so that your doctor can take pictures or video of the large colon. The test helps find ulcers, polyps, tumors and areas of inflammation or bleeding. In some cases during colonoscopy, if a polyp or abnormal tissue is found, your doctor may remove it at that time. During the procedure, a tissue sample (biopsy) of the polyp may be taken for lab analysis to determine whether subsequent surgical removal of the tissue is needed. If caught early, colon cancer is highly treatable and this is the message people should take when deciding to have a colonoscopy or when such a measure is recommended.