Gene may protect some women against breast cancer

WASHINGTON (Reuters) - Scientists have identified a gene variation found in about 13 percent of women of European descent that reduces their risk of developing breast cancer, a study released on Sunday said.

The gene is called CASP8, and women with a certain mutation of the gene were 10 percent less likely than other women to develop breast cancer, according to the study.

The international team of researchers used data on 33,000 women from 14 different studies for their report. Most of the statistics involved women of European descent, the researchers reported in the journal Nature Genetics.

Several gene mutations have been shown to raise the risk of breast and other cancers, including BRCA1 and BRCA2. This is the first variation shown to reduce the risk, however.

Led by Dr. Angela Cox of Sheffield University Medical School in Britain, the researchers focused on CASP8 because it helps damaged cells destroy themselves in a process called apoptosis, or programmed cell death.

Cells are damaged all the time, and usually commit suicide. But when they do not, they may become cancerous.

"This study demonstrates how genes that confer modest effects on breast cancer risk can be identified when sufficiently large data sets are assembled," U.S. National Cancer Institute Director Dr. John Niederhuber said in a statement.

IDENTIFYING RISK

The researchers said their findings have no immediate implications for women.

"But using the same approach we may be able, in the future, to identify a panel of variants with small increases in risk that collectively may put a woman at a much higher risk," said Dr. Montserrat Garcia-Closas of the U.S. National Cancer Institute, who worked on the study.

Just this past week, another team found a new gene that may raise the risk of breast cancer. They found that the PALB2 gene works with the BRCA2 cancer gene to repair genetic damage when both are normal.

Mutations in BRCA2 can prevent it from fixing damaged DNA and preventing cancer. If BRCA2 is normal, but PALB2 is defective, BRCA2 may be out of position for doing its job, and again, damage to the gene can cause a normal healthy cell to become cancerous, said Bing Xia, of the Dana-Farber Cancer Institute and Harvard Medical School in Boston.

"Breast cancer can arise from a wide variety of genetic abnormalities, and mutations acquired during the evolution of breast tumor cells are relatively common in the disease," Xia said in a statement.

"However, only about 10 percent of all cases are the result of inherited mutations, and, of those, only about 20 percent to 30 percent result from mutations in the two main breast cancer-susceptibility genes, BRCA1 and BRCA2. So there is room for other such genes to be discovered."