TELOMERASE ACTIVITY, TELOMERE LENGTH, AND DNA-PLOIDY IN PROSTATIC INTRAEPITHELIAL NEOPLASIA (PIN)

Purpose: To investigate the relationship of telomerase activity, telom ere length, and DNA ploidy in high grade prostatic intraepithelial neo plasia (PIN). Materials and Methods: Tissue samples were carefully mic rodissected to obtain adenocarcinoma or PIN-containing tissue free of cancer. Telomerase activity was measured using the PCR-based telomeric repeat amplification protocol (TRAP). Telomere length was estimated f rom Southern blots of telomere restriction fragments (TRFs). DNA ploid y of PIN and carcinoma was determined by image analysis of adjacent Fe ulgen stained tissue sections. Results: Telomerase activity was found in 4 of 25 samples (16%) of high grade PIN. All telomerase positive PI N foci had a diploid DNA content. Although 5 of 25 samples (25%) of hi gh grade PIN foci analyzed were DNA aneuploid, none of these demonstra ted telomerase activity. Telomerase positive foci of prostate carcinom a (69% of all cancer foci analyzed) displayed heterogeneity in TRF len gth, with a mean TRF length two kilobase pairs shorter than that of te lomerase negative specimens. Conclusions: Telomerase activity is prese nt in a low percentage of high-grade PIN foci, which are diploid by DN A content measurements.