New colon cancer gene discovered

Researchers at Case Western Reserve University and University Hospitals of Cleveland report finding a new gene that is switched off early in the development of colon cancer. The gene, called SLC5A8, is inactivated in 60 percent of human colon cancers, according to their paper in the July 8th issue of the Proceedings of the National Academy of Sciences. "The normal version of the gene suppresses the growth of colon cancer tumors, both in the test tube and when grown in mice," says senior author of the paper, Sanford Markowitz, M.D., a professor in the Ireland Cancer Center and a Howard Hughes investigator at CWRU and UHC. "However, in our study, we found the silencing of this tumor suppressor gene is a common and early event in human colon cancer."

A biochemical process called aberrant methylation turns off the gene. "We have found that we can detect the abnormal methylated SLC5A8 DNA in the blood of certain patients with colon cancer as a marker of the disease,"says Markowitz. This makes the abnormal gene a possible candidate for a new diagnostic test for the early detection of colon cancer, the second leading cause of cancer death in adult Americans.

The researchers also found that the gene transports a mystery substance into the colon cell, by coupling it to the movement of sodium into the cell. "In further studies, we hope to determine the identity of the mystery substance, which could be a potential target for the development of new anti-colon cancer drugs,"says Markowitz.

The research was supported by Public Health Service grants and by the National Colon Cancer Research Alliance.

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