Expression of estrogen (ER) and progesterone receptors, c-erbB-2 oncogene, mutant p53 antioncogene (mp53), e-cadherin adhesion, and apoptotic caspase-8 antigens in tumor relative to matched normal tissue specimens from 102 unselected patients with primary ductal breast carcinoma of various tumor grades was assessed by immunohistochemistry and correlated with patient's biologic and clinical features, such as age, menstrual status, age of menarche, tumor grade and diameter, the presence or absence of metastases, and number of infiltrated lymph nodes. We observed association of e-cadherin adhesion, ER and progesterone antigen marker expression with low histologic grade tumors and limited number of lymph node metastases and of c-erbB-2, mp53, and casp-8 antigen marker expression with high histologic grade tumors and increased number of lymph node metastases. We also observed strong correlation (P<0.05) between 4 of the 6 biomarkers and 4 of the 7 patient/tumor parameters examined. Our findings support the hypothesis of independent expression of these 4 strong biomarkers and reveal that nearly 40% of all breast tumor cases studied express similar proportions of 2 major phenotypic combinations [ER/c-erbB-2/mp53/casp-8: +/+/-/+ (19.6%) & +/-/-/+ (17.8%)]. We conclude that, in agreement with earlier reports, our findings support the diagnostic and potential prognostic value of these markers in the clinical assessment of breast cancer.