For this study, prostate biopsies were obtained from 84 men, with 50% of them being from African Americans and the rest were from white men, with and without PC diagnosis on biopsy. Using fluorescence microscopy with multiplex immunohistochemistry, biopsy tissue samples were stained for four T-cell markers (CD3, CD4, CD8, and FOXP3) and three regions were examined (prostate tumor, normal adjacent to cancer on a biopsy core, and normal). Analyses were stratified by race. An alpha of 0.0125 (after Bonferroni correction p=0.05/4) was used.
The prostate biopsies of African Americans and white men showed several significant differences in T cell expression for multiple markers in the prostate epithelium (Table 1). Most differences were found between normal adjacent prostate epithelium in African Americans compared to normal, normal adjacent, and prostate cancer epithelium in whites. Prostate biopsies in African American men had statistically significant higher levels of CD8 T-cell expression. While there were differences in inflammatory cells distribution in the stroma, these differences were not as marked.
The authors concluded that prostate biopsies from African-Americans consistently expressed higher levels of T-cells compared to those of white men, regardless of PC status. This supports the evidence that African Americans have more chronic inflammation, which may help explain the racial differences seen in PC incidence and mortality. The limitations of this study include the selection bias in the tissue used for analysis, imperfect multiplex staining of tissue, and data that may not be normally distributed.
Table 1 – Differences in T-cell markers between African Americans (AAM) and Whites (EAM) in prostate biopsies:
Presented by: Adriana Vidal, PhD, Cedars-Sinai Medical Center, Los Angeles, California
Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre @GoldbergHanan at American Urological Association's 2019 Annual Meeting (AUA 2019), May 3 – 6, 2019 in Chicago, Illinois