Common cancer gene mutation significantly boosts risk

By Editors

Originally published on August 28 2003 11:00 PM ET

Nearly one in 10 people has a gene mutation that can raise the risk of developing cancer by a quarter or more, researchers reported Thursday. The gene appears to be the most common cancer-linked gene identified so far and raises the risk of breast and ovarian cancer by 50% and the risk of colon cancer by 38%, the researchers said. People with two copies of the mutated gene may double the risk associated with just one of the genes. "The gene was prevalent in around 15 to 16% of the cancer patients, and it was found in around 10% of the general population," said Virginia Kaklamani, an oncologist at Northwestern Memorial Hospital in Chicago, who led the study. "It is very common," she said. By contrast, Kaklamani said, BRCA1 and BRCA2, two gene mutations linked with breast cancer risk, are found in 1 in 500 people.

The newly discovered gene controls a protein called transforming growth factor beta receptor 1-6A, or TGFBR1-6A. The protein is involved in stopping cells from the out-of-control proliferation that characterizes cancer. "This protein has a weird function," Kaklamani said. "In normal cells it inhibits their growth. However, once a cell becomes cancerous it looks like it makes it even more malignant--it accelerates their growth. When inherited, the TGFBR1-6A gene makes people susceptible to having certain cells grow and divide uncontrollably, which may contribute to cancer development."

The researchers analyzed seven published studies and pooled those results to conclude that the TGFBR1-6A gene may be to blame for 7% of all breast cancers, nearly 11% of all ovarian cancers, and 5.5% of all colon cancers. It is less commonly involved in a range of other cancers.

Kaklamani said that while it is too soon to start testing people for the mutation, the study's findings could eventually be used to screen people for cancer risk and perhaps to develop better therapies. She added that her team is now looking to see how aggressive the cancers linked to TGFBR1-6A are and whether mutations can not only be inherited but caused by the environment or behavior.