In view of the limitations of conventional prognostic factors such as differentiation degree, metastatic lymph nodes, hormonal receptors and others, especially when early lesions are found, additional new markers have been studied, such as gene amplification and cell proliferation index, in order to choose the appropriate treatment. Primary breast carcinoma tumors from 97 patients were examined for differentiation degree, metastatic lymph nodes, hormonal receptors, c-erbB-2 amplification and cell proliferation index (Ki-67). A negative relationship with hormonal receptors and c-erbB-2 amplification, Ki-67 and differentiation degree was found, whereas the relationship between c-erbB-2, Ki-67 and differentiation degree was positive. No relationship was found between these factors and metastatic lymph nodes. The concurrence of high cell proliferation index, c-erbB-2 amplification and negative hormonal receptor presence would indicate a subpopulation with a high risk of recurrence. But a larger survival study is necessary to correlate these factors with clinical outcome.