Crucial genetic factor in colorectal cancer found

By Will Dunham

WASHINGTON (Reuters) - Researchers have identified what they see as the leading cause of inherited colorectal cancer -- a genetic abnormality that makes a person about nine times more likely to get the disease.

This trait may explain at least 10 percent and perhaps 15 to 20 percent of colorectal cancer cases, according to Ohio State University's Dr. Albert de la Chapelle, who helped lead the study published in the journal Science on Thursday.

The researchers said in the future a simple blood test should be able to identify people with the trait so they can be screened regularly to catch colon and rectal cancer early when it is most treatable.

"We have identified what appears to be the main cause of inherited colorectal cancer," Dr. Boris Pasche of Northwestern University and Northwestern Memorial Hospital in Illinois, who also helped lead the study, said in a telephone interview.

Colorectal cancer is the fourth most common type of cancer in men and the third most common in women worldwide, according to the American Cancer Society. Globally, about 1.2 million cases of colorectal cancer are diagnosed annually and the disease kills about 630,000 people, the organization said.

Experts believe that about a third of colorectal cancer cases are caused by genetics. Other risk factors include a diet high in fat and calories and low in fiber, obesity, a sedentary lifestyle, heavy drinking and smoking.

The study involved 242 people in central Ohio with colorectal cancer and 195 people who did not have it.

They found that people who had an abnormality related to a gene called TGFBR1 were 8.7 times as likely to develop colorectal cancer than those who did not have the trait.