The prognostic role of ploidy status, S phase fraction, estrogen and progesterone receptor status, and the expression of p53 and erbB-2 protein in male breast carcinoma (MBC) remains controversial. The primary objective of this study was to determine which of the common prognostic factors for female breast cancer predict prognosis in MBC. A secondary objective was to assess the impact of comorbid illnesses on survival. A retrospective review of demographic data, surgical treatment, pathological staging, adjuvant treatment and follow-up was completed for 16 patients with MBC (1 intraductal and 15 invasive). Formalin-fixed, paraffin-embedded tissue was processed for ploidy, S phase fraction, and immunohistochemical detection of estrogen and progesterone receptors plus expression of p53 and erbB-2 protein. Six of 15 patients with infiltrating ductal carcinoma are currently alive without evidence of disease and a median survival of 61 months. Nine patients died after a median survival of 52 months, with 6 patients having no evidence of recurrent breast cancer. Two of 3 deaths secondary to advanced breast cancer occurred in patients who initially presented with T4 lesions and were staged IIIB. Two of 15 tumors were erbB-2 positive, whereas only 1 tested weakly positive for p53 protein. We observed that MBCs express erbB-2 and p53 proteins infrequently. Neither ploidy status, S phase fraction, nor erbB-2/p53 status provided any apparent improvement in establishing prognosis beyond routine pathological staging. Advanced TNM stage was associated with diminished survival. The majority of MBCs express estrogen and progesterone receptors. Survivals in MBC were reduced in association with comorbid medical conditions.