A Medical Device Daily

A genetic mutation already known to be more common in Ashkenazi Jewish breast cancer patients is also prevalent in Hispanic and young African-American women with breast cancer, according to new research out of Stanford University School of Medicine (Stanford, California) and Northern California Cancer Center (NCCC; Union City).

“The message is that these minority breast cancer patients may need screening in ways that we hadn’t appreciated before,” said senior author Alice Whittemore, PhD, professor of health research and policy at Stanford.

She noted that Hispanic women in Northern California, where the study was conducted, derive from different countries than Hispanic women from the East Coast. For that reason, she said that the findings may not apply to Hispanic people in other parts of the country.

Researchers at Stanford and the NCCC reported the finding from a study of 3,181 breast cancer patients in Northern California. It revealed that although Ashkenazi Jewish women with breast cancer had the highest rate of the Breast Cancer 1 (BRCA1) mutation at 8.3%, Hispanic women with breast cancer were next most likely, with a rate of 3.5%. Non-Hispanic whites with breast cancer showed a 2.2% rate, followed by 1.3% of African-American women of all ages and 0.5% in Asian-American women. Of the African-American breast cancer patients under age 35, 16.75% had the mutation.

The research report, published this week in the Journal of the American Medical Association, marks the largest study to date to look at the prevalence of BRCA1 mutations among patients in the four ethnic and racial groups, said lead author Esther John, PhD, research scientist at the NCCC and consulting associate professor of health research and policy at Stanford.

The information could help doctors decide which patients to refer to genetic counseling, the researchers said. They added that they hope the information prompts genetic counselors to develop materials for discussing breast cancer risk in a culturally sensitive way and in languages other than English.

“If a woman has breast cancer, she may ask the question, ‘Could I be a carrier for a BRCA1 mutation? If I am, my daughters and sons need to know it,’” Whittemore said. She said that until now, doctors knew only that Ashkenazi Jewish women were more likely to carry a mutation and therefore frequently referred these women to genetic counseling.

What they didn’t know is how women of different ethnic groups needed to be treated in terms of their BRCA1 status.

“Traditionally studies have focused on white women,” John said. “There is a great need to study racial minorities in the United States.”

The risk of a woman developing breast cancer sometime during her lifetime is about one in eight. Although death rates from the disease are dropping, the American Cancer Society (Atlanta) estimates that 40,000 women will die from breast cancer in 2007.

All people have the BRCA1 gene, which makes a protein that helps the cell repair its DNA. Women who inherit a mutation in that gene from either parent are less able to fix DNA damage and tend to accumulate mutations that lead to cancer. They have a roughly 65% risk of developing breast cancer and 39% risk of ovarian cancer. If one family member tests positive for a mutation, it can alert other women in the family to also get tested and to take preventive measures, the researchers noted.

The study is not the first to focus on which women are most likely to have BRCA1 mutations. A similar study, published in Cancer Research in August 2006, showed that breast cancer patients of Jewish ancestry were “significantly more likely” to have BRCA1 mutations than non-Jewish patients (10.1% compared to 2%) and that Jewish ancestry was one of the most significant predictors for BRCA1 mutations (Medical Device Daily, Aug. 21, 2006).

Prior to the Stanford study, doctors have treated all women other than Ashkenazi Jews as having the same risk level for the mutation. Now doctors who see Hispanic or young African-American breast cancer patients have more information to guide their decisions about referring those women to genetic counseling or testing, the researchers said.

Among other surprises, the research team reported that although mutations can occur throughout the BRCA1 gene, the Hispanic women in the study were more likely to carry a particular mutation that’s also common in Ashkenazi Jewish women. Other ethnic groups carried a wide range of different mutations.

John and Whittemore think the Hispanic women may have this mutation because of their Spanish ancestry. Spain was the home of Sephardic Jews who could have shared the mutation with Ashkenazi Jews of Eastern European origin, they noted.

The researchers said that the prevalence of the mutation in young African-American women with breast cancer also came as a surprise, given that the rate is low in the overall African-American population. The researchers said that the finding is consistent with a long-known pattern that when young African-American women get breast cancer, the disease tends to be particularly aggressive, which is a hallmark of tumors that arise from BRCA1 mutations.

However, Whittemore said that while the information doesn’t change how doctors treat those tumors, it could help prompt more doctors to recommend genetic counseling for young African-American breast cancer patients.

The National Cancer Institute of the National Institutes of Health funded the study.

Other Stanford researchers who participated in this study include Gail Gong, PhD, a research associate; Anna Felberg, a programmer in health research and policy; Dee West, PhD, professor of health research and policy at Stanford and chief scientific officer at the NCCC; and Amanda Phipps, epidemiologist at the NCCC.