Book excerpt: This Prostate Cancer Center Initiation grant has been designed to identify genetic and molecular markers of prostate cancer progression within and between racial ethnic groups (African-Americans, Latinos, Whites, Japanese) at substantially distinct underlying risk of prostate cancer. Our Epidemiology Core has obtained signed tissue releases from 410 prostate cancer patients to date identified during follow-up of the Hawaii/Los Angeles Multiethnic Cohort study. One-hundred eight-five tissue samples have been received and processed histopathologically by Project C, which has begun immunohistochemical staining for p27, p21 and p16 markers with additional markers to follow. Project B, studying the androgen receptor (AR) gene in detail, has identified 21 sequence variants in 58 samples analyzed to date; one mutation was shown in culture to be twice as active as wild-type AR. In Project A, studying the SRD5A2 gene in detail, 24 sequence variants were found in 30 tumors with three mutations (A495, G692A and V63M occurring on a recurring basis.