Which brings us back to breast cancer. Not only rates, but breast cancer patterns differ between black and white women. When diagnosed, black women are more likely to be under the age of 35 and to die by the age of 50. Some have argued that their tumors spread more quickly because they differ physiologically from white women. Black women tend to lack key hormone receptors, which means that tumors respond poorly to familiar hormone-based treatments.
Physician and cancer researcher Olufunmilayo Olopade noticed these differences and originally assumed that they were due to genetic, race-based differences between white women and women of African origin. Recently, however, she has begun to see things differently, looking to how women of color embody the daily stresses of racism and economic deprivation. The absence of hormone receptors could be a function of environmental factors, but, seeking other explanations, Olopade has teamed up with University of Chicago biopsychologist Martha McClintock to ask a new kind of question. In a study of mice that primarily modeled the growth rate for human breast cancer, they have shown that socially stressed mice express certain genes differently in their mammary tissue. Specifically, the stressed mice demonstrate an uptick in expression for suites of genes involved in lipid metabolism and a biochemical pathway that converts sugars into energy. Both pathways contribute to breast cancer growth. The stressed mice are genetically the same as unstressed controls, but it’s not what genes you have that count so much as which genes your cells express.
This excerpt was part of the author’s discussion of Dorothy Robert’s Fatal Invention: How Science, Politics, and Big Business Re-Create Race in the Twenty-first Century.