Possible Breast Cancer Prevention Strategy

Breast cancer genes identified could help prevent estrogen receptor positive cancers

(RxWiki News) The day has come when scientists are working on ways to prevent cancer from ever developing. It involves looking for certain genes in people at risk for various cancers.

A new study has identified 13 genes that may help predict if a woman is at high risk of developing breast cancer that’s driven by estrogen.

Women at risk include those who have a close relative who has had breast cancer and women who have had changes in their breasts.

These findings could help tailor treatment for at-risk women with medications that may prevent the disease. These genes may also become targets for new therapies.

"Research breast cancer risk factors."

Seema Khan, MD, co-leader of the breast cancer program at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University, led the research.

The majority of diagnosed breast cancers are fed by the female hormone estrogen. As such, they are called estrogen-receptor positive (ER+) breast cancers. Breast cancers that are not sensitive to estrogen are called estrogen-receptor negative (ER-).

Certain drugs such as tamoxifen and Evista (raloxifene) block estrogen and can be used to try to prevent breast cancer from ever developing. These medicines have side effects and risks, though, such as joint pain and increased risk of brittle bones (osteoporosis). These medications are effective only on ER+ breast cancers, not ER- or other forms of the disease.

Because of these side effects, women at risk have been unwilling to take the medications.

“We should not expose women at risk for hormone-insensitive breast cancer to the side effects of preventive medications that we know will not work for them," Dr. Khan said in a press release. "Moreover, if we knew who these women were, we could focus on them in terms of designing new studies to find a solution for preventing hormone-insensitive cancer."

Earlier research has shown that if women with breast cancer develop the disease in the other breast, the second cancer will most likely have the same hormone sensitivities. Knowing this, the researchers analyzed the genes in the unaffected breasts of 30 women with ER+ breast cancer and 15 women with ER- breast cancer.

The findings were confirmed with another group of women with both types of breast cancer and a control group of 12 women who did not have breast cancer.

Researchers pinpointed high levels of 13 genes in the women with ER- breast cancer. Eight of the genes are involved in fat metabolism, which researchers found surprising.

"This was interesting because obesity is a breast cancer risk factor for postmenopausal women, but obese women are generally thought to be at increased risk for hormone-sensitive cancer," Dr. Khan said.

"It will be a few more steps before this information is practically useful, but we are hoping that it can take us to a place where we can obtain a breast sample from healthy women, see that they are at risk for a certain type of breast cancer and tailor the prevention strategy accordingly," Dr. Khan said.

This study was published March 19 in the journal Cancer Prevention Research, a publication of the American Association of Cancer Research. This work was supported by the Lynn Sage Cancer Research Foundation, the Avon Foundation and a donation from Ms. Dariel Eklund. No conflicts of interest were disclosed.

Review Date: 
March 19, 2013