Study Explains Gene’s Role in Colon Cancer

When a cancer-blocking gene turns bad, it actually helps another gene start the process that leads to cancer of the colon, researchers have found.

A gene called APC normally deactivates a cancer-causing gene called c-MYC, but when APC is mutated it actually turns on the cancer gene, causing the uncontrolled growth of cells in the colon, according to researchers at Johns Hopkins University and the Howard Hughes Medical Institute in Baltimore.

A report on the gene discovery is published today in the journal Science.

Dr. Bert Vogelstein, a Hopkins researcher who discovered the cancer-suppressing action of APC, said he and his colleagues have found that the mutation of APC is a key step in developing colon cancer.

“Cancer is like a car with the accelerator pushed to the floor and with failed brakes,” Vogelstein said in a statement. For colon cancer, he said, “c-MYC is the accelerator and APC is the failed brakes.”

APC is normally a suppressor gene that keeps cells from multiplying out of control. When the gene is mutated, either through heredity or as the result of exposure to certain chemicals, it sends a signal to the c-MYC gene that causes cells to multiply out of control, the study found.

Researchers said the finding may help develop drugs that will block the signal that causes the c-MYC gene to turn on.

Science is the journal of the American Assn. for the Advancement of Science.