Ethnic differences in neuroendocrine cell expression in normal human prostatic tissue

Objectives. To determine whether any differences exist in neuroendocrine (NE) cell differentiation in normal prostates among various ethnic groups because the incidence and mortality from prostate cancer vary across racial groups. Methods. Archived paraffin-embedded prostate samples not containing any malignancy were obtained from cystoprostatectomy specimens. Prostatic tissue was obtained from 15 African Americans, 13 Hispanics, 15 Asians, and 16 whites. NE cells were identified based on immunoreactivity for chromogranin A. The mean number of NE cells per high power field (HPF) for each patient was determined using a visual quantitative method by two observers who were unaware of the race of the patients. Results. The geometric mean number of NE cells was 6. 1/HPF for Asians, 5.6/HPF for whites, 4.0/HPF for Hispanics, and 0.7/HPF for African Americans. A highly significant difference was observed in the distribution of NE cells between African Americans and each of the other races (P <= 0.003). A trend toward greater NE expression was noted in Asians and whites compared with Hispanics; however, this difference did not reach statistical significance. Conclusions. We found a fivefold to eightfold difference in the distribution of NE cells in the normal prostates of African-American men compared with that of other races. The comparatively low NE cell expression in African-American men may play a role in the greater rate of prostate carcinogenesis seen in this ethnic group. (c) 2005 Elsevier Inc.