OBJECTIVE To identify differences in clinical characteristics, histological features, hormone receptor status, and tumor marker expression between patients with sporadic and familial breast cancer. METHODS As in the previous Part I of this study, two groups of women with breast cancer were compared. The first group (group I) included 504 patients with a family history of breast cancer. The second (control) group (group II) consisted of 300 patients not reporting such a history in their relatives. The examined parameters in this report were stage and axillary lymph node involvement at the time of the initial diagnosis, treatment methods, hormone receptor status, and serum levels of the tumor markers CEA and CA 15.3. The data were processed and analysed using the SPSS statistical package. The statistical significance of differences between groups and subgroups was evaluated by x(2) Pearson's test and Student's paired t-test. RESULTS Compared to sporadic cases, patients with familial breast cancer were more often diagnosed at an advanced III or IV stage; metastatic involvement of the regional lymph nodes was more frequent in group I patients. In the same group more radical surgical procedures combined with chemotherapy and local irradiation were performed. In group I the percentage of negative hormone receptors was higher (35.3% versus 22.6%; p <0.0001) for estrogen receptors (ER), and 47.6% versus 32.6% (p <0.0001) for progesterone receptors (PR). Also, in group I raised serum levels of CA 15.3 were significantly more frequent compared with group II (48% versus 35.5%, p <0.0789), and this applied also for CEA values above 50 ng/ml (10.6% versus 1.5%, p <0.0002). CONCLUSIONS Familial breast cancer displays particular clinical characteristics, distinguishing it from the sporadic type of the disease. Patients with familial breast cancer are usually diagnosed at an advanced stage. Commonly, the hormone receptors are negative and the serum concentrations of tumor markers elevated. The steroid receptor status represents the most reliable predictor of response to hormonotherapy and an important prognostic factor of the patient's outcome. As a result of their particular characteristics, these patients require more radical surgical techniques combined with pre- or postoperative local radiotherapy and systemic chemotherapy.