Critical analysis of the evidence supporting the use of prognostic markers is needed for these to be used most appropriately in patient management. The College of American Pathologists recently sponsored a national conference to review the status of tumor markers for carcinomas of the breast, colon, and prostate gland. The conclusions of the Prostate Cancer Working Group are presented in this report. Currently, the TNM (Tumor, Lymph Node, Metastasis) staging system, histologic grading (Gleason system), and serum prostate-specific antigen are recommended for general use as prognostic markers in prostate cancer. Data support the use of DNA ploidy analysis in specific clinical settings, although general use is not currently recommended. The Working Group concluded that other markers do not have sufficient support in the literature to recommend routine use at the present time.