Prostate cancer is a leading cause of cancer death in US men. Yet, the etiology of prostate cancer remains poorly understood, with only older age, African ancestry, family history of the disease, and multiple germline genetic variations being established disease risk factors. Prostate cancer occurs more often in African-American men and Caribbean men of African descent than in men of other race/ethnicities. The causes of these racial and ethnic differences are multifactorial, but it has been proposed that differences in tumor biology contribute to the health disparity associated with prostate cancer.

Previously, our laboratory discovered immunobiology differences between African-American and European-American men where genes involved in the inflammatory response tended to be up-regulated in tumors of African American patients. Accumulating evidence suggests that inflammation may be involved in prostate carcinogenesis. Given these observations, we hypothesized that inflammation may contribute to prostate cancer risk and the survival health disparity observed between African-Americans and European-Americans. To this end, we conducted a case-control study in the greater Baltimore area where we recruited 1000 cases and 1000 controls composed of equal populations of African-American and European-American men. In our survey, we asked about non-steroidal anti-inflammatory drugs (NSAIDs) use categorized into aspirin, Tylenol, and other pain relievers that neither contain Tylenol nor aspirin. We found a significant association between aspirin use and prostate cancer risk—where aspirin use decreased the risk of prostate cancer. Strikingly, the decreased prostate cancer risk as a result of aspirin use was most profound in African-American men. We were also able to measure the levels of C-reactive protein, a marker for inflammation, to further evaluate the relationship between aspirin use, inflammation, and prostate cancer risk. Indeed, we did observe a decrease in C-reactive protein in patients who took aspirin. Interestingly, overall levels in healthy controls and prostate cases were higher in African-American subjects and patients when compared to European-Americans. Although aspirin use decreased C-reactive protein levels in African-American and European-American cases, African-Americans had significantly higher levels of C-reactive protein. The robust association between aspirin consumption and prostate cancer risk suggests that inflammation might be a driver in prostate cancer of African-American men. Additionally, the increased levels of C-reactive protein in African-American controls and cases might contribute to the excessive disease risk and mortality among these men.

Citation Format: Cheryl J. Smith, Symone Jordan, Tiffany H. Dorsey, Dean Mann, Chris A. Loffredo, Elise Bowman, Wei Tang, Stefan Ambs. Aspirin use among African American men reduces prostate cancer risk: Findings from the NCI-Maryland Prostate Cancer Case-Control study. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1776.