Flow cytometric analysis of cellular DNA in human prostate cancer: relationship to 5 alpha-reductase activity of the tissue.

Flow cytometry of 20 prostate cancer specimens was carried out and the percentage DNA content in each phase of the cell cycle was correlated to the 5 alpha-reductase activity of the tumour. A group of 20 hyperplastic specimens was also entered into this study as control. Tumours were divided into 3 groups on the basis of their 5 alpha-reductase activity. This classification made it possible to identify a group of tumours of which none formed metastases (diploid tumours with 5 alpha-reductase activity greater than 20 pmol/mg protein/30 min and with less than 10% of the cells undergoing mitosis) and a second group of which 78% had metastasised at the time of presentation (diploid tumours with 5 alpha-reductase activity less than 10 pmol/mg protein/30 min and with more than 15% of the cells undergoing mitosis). DNA content within each of the 5 alpha-reductase groups appeared also to correlate with the histological grade of the cancer but no relationship was established with the stage of the disease. Our results suggest that a multi factorial discriminant combining DNA ploidy and 5 alpha-reductase measurements offers a good prognostic index for the assessment of disease progression in prostate cancer and that this might form the basis of a new approach to the treatment of this disease.