Cancer researchers and clinicians need to adopt a new attitude toward race classifications as interracial parentage in the United States continues to increase. I want to uncouple race and genetics, stated Edison Liu, MD, at the 1997 Biennial Symposium on Minorities, the Medically Underserved, and Cancer held in Washington, DC.
Dr. Liu, director of the Division of Clinical Sciences at the National Cancer Institute, stated that traditional racial categories do not accurately reflect genetic factors that could be crucial in breast cancer survival. In fact, cancer biomarkers show no differences along racial lines.
Psychosocial vs Genetic Considerations
Interracial parentage continually increases the number of Americans born of mixed racial heritage, and racial assignments and loyalties are starting to reflect psychosocial rather than genetic considerations. Cancer-related genes, therefore, will increasingly appear in individuals apparently outside a supposed target group.
For example, a woman who identifies herself as black but who has a Jewish grandparent may be as likely to carry a supposedly Ashkenazi Jewish mutation as a woman who identifies herself as white and Jewish. Neither womans racial identity will have any bearing on her prognosis. Knowledge of her ethnic background, however, may prove critical to appropriate selection of treatment strategies and, ultimately, her survival.
Social and Cultural Factors
The fact that black women currently experience higher breast cancer mortality than do white women, despite lower incidence, reflects social rather than strictly medical or genetic factors, Dr. Liu emphasized. There is no single race gene, and no selection for cancer in defining race, he said. Lower socioeconomic status, delayed detection, less than optimal treatment, and perhaps a culturally based reluctance to secure treatment appear to account for the black-white survival discrepancy, Liu stated. Data suggest that race has no effect on survival if tumors and treatments are equal; one must therefore conclude that many black women probably do not receive adequate treatment, he said.
Race should be considered a surrogate for socioeconomic group membership and be used to uncover socioeconomic factors that may affect cancer incidence or treatment, Dr. Liu urged. Clinical trials often lack the statistical power to uncover population differences in minority groups, he added. For that reason, blacks and other minorities should be oversampled. Receiving adequate care is the key to optimizing survival in all racial and ethnic groups, he concluded.