Breast Cancer :: Genetic alterations may explain racial disparity in breast cancer

Molecular and genetic alterations that cause tumors and drive the course of disease may someday explain the differences in incidence and mortality between African American and European American breast cancer patients. This is the conclusion of a literature review by a research team at Roswell Park Cancer Institute (RPCI) led by Christine B. Ambrosone, PhD, Chair of Epidemiology at RPCI. Results of the study are published in the September edition of Cancer Research.

Epidemiologic data gleaned from studies over the years have documented differences in breast cancer incidence and mortality rates between African American and European American women. However, even after controlling for variables such as stage at diagnosis, access to health care, treatment, co-morbid illness, marital status and other pathological and sociodemographic variables, disparities remained between these populations.

?These data point to possible differences in the nature of the disease itself, supported by the observation that breast cancer in African American women is more aggressive at presentation, characterized by an increased prevalence of high-grade, hormone receptor negative tumors,? according to Dr. Ambrosone. This review focused on tumor biology to explain the differences among breast cancer patients in these populations.

The researchers found that significantly more African American women present with aggressive, grade 3, estrogen- and progesterone-negative tumors than their European American counterparts. Further, African American women are more likely to have a distinct subtype of breast cancer and other molecular characteristics that are all consistent with a poorer prognosis.

Interestingly, when the researchers reviewed the literature on breast cancer epidemiology, tumor biology and genetics in Africa, they found striking similarities between African American and sub-Saharan African women. ?It is possible that these similarities are influenced by a genetic component,? notes Dr. Ambrosone, ?or by a lack of variation in the distribution of environmental or lifestyle factors that influence breast cancer risk.?

To date, genetic and non-genetic factors that may predict this early onset, aggressive breast cancer in African American women have not been identified. However, the study team is now investigating factors that may predict these racial differences in breast cancer epidemiology. Determination of these factors may lead to the identification of women who are susceptible, particularly at a younger age, and enhance targeted screening efforts and preventive interventions. Further, evaluation of risk factors, while accounting for factors related to socioeconomic status, may also delineate the proportion of higher mortality attributed to tumor characteristics.

Roswell Park Cancer Institute, founded in 1898, is the nation’s first cancer research, treatment and education center and is the only National Cancer Institute-designated comprehensive cancer center in Upstate New York.? RPCI is a member of the prestigious National Comprehensive Cancer Network, an alliance of the nation’s leading cancer centers. For more information, visit RPCI’s website at

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