Health disparities: genetics plays an important role in cancer detection, prognosis among minorities

SAN DIEGO – Research reported at the 2008 Annual Meeting of the American Association for Cancer Research, April 12-16, suggests that poorer outcomes for breast cancer and prostate cancer among minorities may be due to biologic factors. In addition, researchers present a new theory on why a recent decline in breast cancer rates was less pronounced among African-American women, and offer data on a relatively simple means of reducing racial disparities in breast cancer care.

Gene expression differences in primary breast tumors from African American and Caucasian Women: Abstract 555

Researchers have found that gene expression in breast tumors differs between African-American and Caucasian patients in ways that might help explain why the disease is more deadly in African-American women and why it strikes these women at an earlier age. Although more Caucasian women are diagnosed with breast cancer overall, their cancers tend to be less aggressive and generally occur later in life, investigators report.

Researchers at the Windber Research Institute in Windber, PA, found 65 genes were differentially expressed between tumors in the two racial groups. Of these, 28 genes were more highly expressed in African-American patients and 37 genes had lower expression. Although most of the genes have not been previously linked to cancer, some are known to be associated with tumor progression or suppression.

“This study suggests that in addition to the socioeconomic and health care factors that have been found to play a role in breast cancer outcomes, there may also be molecular differences that contribute to the more aggressive clinical features of breast tumors in African-American women, compared with Caucasian women,” said lead investigator Lori Field, Ph.D., a postdoctoral fellow in the women’s health research program at the institute.

According to Field, African-American women have the highest mortality rate from breast cancer among ethnic groups in the United States. “With further study, these genes may prove to be promising new molecular targets to which new therapies can be developed to better treat the breast tumors in African-American women as well as improve outcomes in this population,” Field said.

The research is part of the Clinical Care Breast Project, a federally mandated and funded collaboration between the Windber Research Institute and Walter Reed Army Medical Center in Washington D.C. In this study, the researchers obtained breast tumor samples from 26 pairs of African-American/Caucasian women, who were matched in age and breast cancer stage, as well as in the care they received from Walter Reed. They obtained RNA from these samples to produce gene expression profiles, which they then compared between the groups.