Relationship between DMA Ploidy, Glandular Differentiation, and Tumor Spread in Human Prostate Cancer1

DNA ploidy was evaluated by flow cytometry for 45 human prostate carcinomas (34 prostatectomy specimens and 11 biop sies). Twenty tumors (44.4%) contained a distinct aneuploid stem line. All 11 tumors confined to the prostate gland (pathological Stage B) were diploid. The frequency of aneuploidy increased with advancing stage, and most tumors with distant métastases were aneuploid. The degree of glandular differentiation was characterized by the Gleason score. One-third of tumors with a Gleason score of 5 to 6 were aneuploid, whereas over 70% of poorly differentiated tumors with a Gleason score of 9 to 10 were aneuploid. Among diploid tumors, 45.5% were localized carcinomas (Stage B), 36.4% were characterized by invasion outside the prostate (Stage C), and 18.2% formed pelvic nodal or distant métastases(Stages D-,and D2). In nearly two-thirds of patients with aneuploid tumors, pelvic nodal or distant métas tases were found. When tumors were classified according to both DNA ploidy and degree of glandular differentiation, then subgroups of tumors with the highest and lowest degree of malignant potential became apparent. Only 7.1% of diploid tu mors with a Gleason score of 5 to 6 formed métastases, but 80% of aneuploid tumors with a higher Gleason score (7 to 10) formed métastases.Diploid tumors with higher Gleason scores and aneuploid tumors with lower Gleason scores had interme diate frequencies of métastases.The presence of an aneuploid stem line in prostate carcinomas indicated that the tumor had spread outside the prostate gland or had metastasized. DNA ploidy may be an important prognostic factor for human prostate cancer. DNA ploidy and the degree of glandular differentiation considered together may improve prognostic evaluation of pros tate carcinomas.