p16 (CDKN2/MTS1) gene deletions are rare in prostatic carcinomas in the United States and Japan

Purpose: The incidence of clinically apparent prostatic carcinoma is much higher in the United States than in Japan. Alterations in the p16 tumor suppressor gene have been identified in various tumor types, including cultured prostatic carcinoma cell lines. We studied the possible deletions of either exon 2 or 3 of this gene in primary clinical prostatic carcinomas from Japan and the United States. Materials and Methods: Genomic DNA was extracted from 36 formalin-fixed, paraffin-embedded clinical prostatic carcinomas from Japan and 27 carcinomas from the United States. Exons 2 and 3 of the p16 gene were amplified using comparative multiplex polymerase chain reactions (PCR) and then analyzed for possible deletions of either exon. Results: Two out of 36 (5.6%) carcinomas from Japan clearly demonstrated deletion of p16 exon 2, but this deletion was not detected in any of the 27 carcinomas from the United States. Conclusions: Although slightly higher in Japan than in the United States, the frequency of p16 exon deletions in clinical prostatic carcinomas is very low, and probably is not important in the development of this neoplasm.