Nuclear DNA analysis of prostate tissues: correlation with stage and grade of tumour

Flow cytometry was used to analyse the DNA content of 20 unfixed prostatic specimens obtained from patients with cancer of the prostate. The tumours were of different stages and grades of differentiation and the numbers of cells in each phase of the cell cycle were compared to those obtained from 26 patients with benign prostatic hyperplasia. It was noted that, as the cancer progressed from a well to a poorly differentiated state, there was a distinct shift in the distribution of cells in the G0/G1 phase towards the S and G2+M phases. This was particularly marked in cases with a summed Gleason score of 7-10, and was independent of the stage and bulk of the tumour. Furthermore, all tumours with a Gleason score of 7 or more exhibited a tetraploid histogram, whereas only 2 of 14 patients with a well or moderately well differentiated cancer had tetraploid histograms. Two patients were found to have tumours with aneuploid DNA content, and both died within 2 years from the time of diagnosis. Although it is too early to speculate on the place flow cytometry in the clinical management of patients with cancer of the prostate, the results generated from this present study suggest that flow cytometry may be capable of providing prognostic information not supplied from histopathological analysis.