Tests for estrogen (ER) and progesterone (PR) receptors, c-erbB-2, p53 and Bcl-2 were made on paraffin sections of thirty-three cases of invasive micropapillary carcinoma (MPCa) of the breast. The relations between these proteins and general parameters and the patients' evolution, were analyzed and their statistical significance determined by Fisher's exact test. Follow up was available on twenty one patients of whom thirteen were alive after a mean of sixty months. Tumor size, metastatic nodes, c-erbB-2 and Bcl-2 all showed higher values in the dead patient group, but only nuclear grade and extensive lymphatic vessel invasion (LVI) were statistically significant prognostic factors. Hormone receptors and oncogenes were positive in quite similar figures to those of common breast cancers (NOSCa) and offered supplementary information about differentiation and cell atypia of individual cancers. Accordingly, ER (72.7%), PR (45.4%) and Bcl-2 (69.6%) were directly interrelated and inversely related with nuclear grade, mitotic grade, c-erbB-2 (36.3%) and p53 (12.1%). In conclusion, MPCa is a lymphotropic cancer phenotype whose prognosis can be influenced by known prognostic factors, including molecular. The lack of discriminative power between MPCa and NOSCa of ER, PR, c-erbB-2, p53, and Bcl-2 reinforces the importance of recognizing this particular type of cancer.