Telomerase activity, telomere length, and DNA ploidy in prostatic intraepithelial neoplasia (PIN)

Purpose: To investigate the relationship of telomerase activity, telomere length, and DNA ploidy in high grade prostatic intraepithelial neoplasia (PIN). Materials and Methods: Tissue samples were carefully microdissected 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 from Southern blots of telomere restriction fragments (TRFs). DNA ploidy of PIN and carcinoma was determined by image analysis of adjacent Feulgen stained tissue sections. Results: Telomerase activity was found in 4 of 25 samples (16%) of high grade PIN. All telomerase positive PIN foci had a diploid DNA content. Although 5 of 25 samples (25%) of high grade PIN foci analyzed were DNA aneuploid, none of these demonstrated telomerase activity. Telomerase positive foci of prostate carcinoma (69% of all cancer foci analyzed) displayed heterogeneity in TRF length, with a mean TRF length two kilobase pairs shorter than that of telomerase negative specimens. Conclusions: Telomerase activity is present in a low percentage of high-grade PIN foci, which are diploid by DNA content measurements.