Flow Cytometric DNA Analysis of Prostate Adenocarcinoma :Correlation with histologic grade and DNA ploidy

ABSTRACT

Nuclear DNA content of 32 cases of prostate adenocarcinoma diagnosed 1986-1991 was determined by flow cytometry, with the use of paraffin-embedded archival tissue. The present study was done to define the relationship between clinical stage, histopathological grade, and DNA ploidy. Aneuploidy was found in 10(31.3%) cases including 7 cases of near-tetraploidy. Among diploid tumors, 36.4% were localized disease(stage A and B), 13.6% were characterized by invasion outside the prostate(stage C), and 50.0% showed distant metastasis(stage D). Among aneuploid tumors, 10.0% were stage B, 50.0% stage C, and 40.0% stage D. The degree of glandular differentiation was characterized by the Gleason score and the percentage of sampled tissue involved by carcinoma was graded by Dhom's method. Apparent correlation was found between Gleason grade and Dhom grade(P<0.05). All 13 tumors with a Gleason grade I(score of 2 to 5) were diploid. Four of 9 tumors with a Gleason grade II(score of 6 to 7) were aneuploid(near-tetraploidy 33.3%, aneuploidy 11.1%) and 60.0%, of tumors with a Gleason grade III(score of 8 to 10) were aneuploid(near-tetraploidy 40.0%, aneuploidy 20%). The percentage of aneuploid cases increased with advanced clinical stage, but the relationship between aneuploidy versus clinical stage was not significant. However, it can be concluded that DNA ploidy correlates well with Gleason grade(p<0.05), which may have predictive prognostic value for prostate adeno-carcinomas.