Biological aggressiveness evaluation in prostate carcinomas:immunohistochemical analysis of PCNA and p53 in a series of Gleason 6 (3+3) adenocarcinomas

We selected 63 prostate tumors with Gleason's grade 6 (3+3), commonly showing both tubular and cribrous patterns. We compared in both patterns the expression of two of the most used biologic markers: PCNA and p53, with the aim to verify the validity of the Gleason's grading system to compare the morphologic grade with biologic aggressiveness and prognostic value. We did not find any statistical difference in the protein immunopositivity, indicating that both patterns could have identical biologic behaviour; then we confirmed the validity of Gleason's system for considering both tubular and cribrous patterns as an intermediate grade of tumoral differentiation. Moreover, we found a linear relationship between the increase of PCNA and the accumulation of mutated p53; this datum could confirm the hypothesis that p53 mutation is a late event in prostate carcinogenesis.