Developments in Brief : Gene Mutation May Be Linked to Colon Cancer

Researchers have discovered an important step in a process of a gene mutation that appears to play a crucial role in the development of colon cancers, the second most prevalent form of cancer.

In two separate studies published simultaneously in the current issue of Nature, the British science journal, researchers said they found that a normal gene, which is called ras and is found in cells lining the colon and rectum, can mutate into an oncogene that spurs cancerous growth.

“Our eventual hope is that by understanding the mechanism of tumors we will perhaps be allowed an intelligent way to design preventive measures,” said Dr. Bert Vogelstein of the Johns Hopkins University School of Medicine and a co-author of one report.

In colon cancer, cells along the lining of the colon or rectum grow to form polyps, which then become cancerous. Vogelstein said cells must undergo a series of genetic mutations before reaching the cancerous stage.

In his study, Vogelstein found 11 of 27 colorectal tumors contained a ras oncogene. In the other study, researchers at the State University of New York in Stony Brook found 26 of 66 colorectal tumors had the ras oncogene.

Oncogenes are genes that have many functions in cells, including protein synthesis and reproduction. When mutated or activated in a certain way, however, they can trigger cancer. Just how this happens is still a mystery.

An estimated 145,000 Americans will be diagnosed with colorectal cancer this year and 60,000 will die, making it second only to cancer of the lung, according to the American Cancer Society. Evidence suggests the cancers may be linked to a high-fat, low-fiber diet, according to the society.