Genetics May Explain Racial Disparity in Colon CA Outcome

Genetic differences may contribute to the higher mortality associated with colon cancer in African-Americans compared with Caucasians, according to recent research

John M. Carethers, M.D., of the University of Michigan in Ann Arbor, and colleagues examined the prevalence of microsatellite instability (MSI) and associated CD8⁺ T cell infiltration within the cancers for a population-based cohort of 503 patients (45 percent African-American) with colon cancer.

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The researchers found that, among Caucasian patients with colon cancer, 14 percent of the cancers showed MSI compared with 7 percent in African-Americans (P = 0.009). Clinically, no differences in MSI cancers were observed between the races. For patients with microsatellite stable cancers, African-American patients were more likely to be younger and female and have proximal cancers, compared to Caucasian patients. CD8⁺ T cell infiltration was significantly greater in MSI cancers, but no difference was observed according to race.

“Utilizing this population-based cohort, African-American cancers show half the MSI prevalence of Caucasians without change in CD8⁺ T cell infiltration which may contribute towards their higher mortality from colon cancer,” the authors write.