Gene May Shield Women From Cancer -- Study

About one-fifth of Hispanic women have a genetic variation that offers
significant protection against breast cancer risk, according to a new
study.

The genetic variant originates from native Americans and reduces
breast cancer risk by 40 per cent to 80 per cent, particularly the
more aggressive estrogen receptor-negative forms of the disease,
researchers said.

"The effect is quite significant," study senior author Dr. Elad Ziv, a
professor of medicine at the University of California, San Francisco,
said in a university news release.

"If you have one copy of this variant, which is the case for
approximately 20 per cent of US Latinas, you are about 40 per cent
less likely to have breast cancer. If you have two copies, which
occurs in approximately one per cent of the US. Latina population, the
reduction in risk is on the order of 80 per cent," Ziv explained.

The researchers pinpointed the genetic variant after analyzing DNA
from 3,140 breast cancer patients in the United States, Mexico and
Columbia, as well as from nearly 8,200 women without breast cancer in
those same countries.

The team also found that women with the genetic variant have breast
tissue that appears less dense on mammograms.

Breast tissue that appears more dense on a mammogram is a known risk
factor for breast cancer, according to the study published in
thejournal Nature Communications.

Hispanic women are at lower risk for breast cancer than women in other
ethnic groups. Lifetime risk of the disease is 13 per cent for whites,
11 per cent for blacks, and less than 10 per cent for Hispanics,
according to the US National Cancer Institute.

The risk is even lower for Hispanic women with native American ancestry.

The newly identified genetic variant is on chromosome 6, near a gene
that codes for an estrogen receptor called ESR1. Further research is
needed to determine how the genetic variant affects breast cancer
risk, the researchers said.
--New York Times