Racial and ethnic differences in the biology of breast cancer tumors

Scientists from the National Cancer Institute are looking into the racial and ethnic differences in the biology of breast cancer tumors and are presenting their findings this week at the American Association for Cancer Research conference on The Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved, being held November 27-30 in Atlanta.

While observed differences in breast cancer survival between African-American and Caucasian women are often attributed to disparities in socio-demographic and access to healthcare factors, recent studies have shown that, even when accounting for these factors, African-American women still fare worse than Caucasian women.

In a study of how genes are activated in breast cancer tumors, researchers at the National Cancer Institute (NCI) have demonstrated that there are discernable racial and ethnic differences in the biology of these tumors.

In particular, their findings revealed that many genes related to tumor immunobiology, inflammation, and angiogenesis are expressed differently in tumors from African-American women than in those from Caucasian women. The data could indicate that inflammation and other immune system processes play a stronger role in the development and progression of cancer in African-American women, says Damali Martin, Ph.D., postdoctoral fellow at NCI’s Center for Cancer Research.

According to Martin, African-American breast cancer patients on the whole tend to have a greater prevalence of a more aggressive form of breast cancer, one that is less likely to respond to hormone therapy and more likely to spread to lymph nodes.

Martin and her colleagues examined gene expression profiles – an indicator of which genes are active - in microdissected breast tumors from 35 patients with invasive breast cancer, including 18 African Americans and 17 Caucasians.

The researchers identified racial discrepancies in the gene profiles that point to significant differences in several biological pathways, including how tumor cells interact with the immune system and the mechanisms for angiogenesis – the development of blood vessels that feed tumors. The researchers point out that many of these genes are also active in inflammatory diseases. Previous research has shown a link between inflammatory diseases, such as chronic cholitis, and cancer, Martin says.

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The mission of the American Association for Cancer Research is to prevent and cure cancer. Founded in 1907, AACR is the world's oldest and largest professional organization dedicated to advancing cancer research. The membership includes nearly 26,000 basic, translational, and clinical researchers; health care professionals; and cancer survivors and advocates in the United States and more than 70 other countries. AACR marshals the full spectrum of expertise from the cancer community to accelerate progress in the prevention, diagnosis and treatment of cancer through high-quality scientific and educational programs. It funds innovative, meritorious research grants. The AACR Annual Meeting attracts more than 17,000 participants who share the latest discoveries and developments in the field. Special Conferences throughout the year present novel data across a wide variety of topics in cancer research, treatment, and patient care. AACR publishes five major peer-reviewed journals: Cancer Research; Clinical Cancer Research; Molecular Cancer Therapeutics; Molecular Cancer Research; and Cancer Epidemiology, Biomarkers & Prevention. Its most recent publication, CR, is a magazine for cancer survivors, patient advocates, their families, physicians, and scientists. It provides a forum for sharing essential, evidence-based information and perspectives on progress in cancer research, survivorship, and advocacy.