A group of 350 unselected breast cancer patients, treated at the Center of Oncology in Cracow, Poland, between January 1992 and December 1994, was analyzed. The following reciprocally interrelated histologic characteristics were evaluated: 1) histologic tumor type (considered in 3 categories of aggressivity), 2) tumor grade (according to Scarf-Bloom-Richardson), 3) constituent of in-situ carcinoma in invasive cancers and characterization of breast lobuli, 4) tumor growth pattern (microfocal, macrofocal or mixed), 5) invasion of nerves, 6) vascular invasion by cancer cells in tumor surroundings, 7) extensiveness of tumor necrosis, 8) involvement of the breast distant from the tumor mass by cancer cells, 9) status of axillary lymph nodes, 10) invasion of metastatic lymph node surroundings. Metastases in axillary lymph nodes were independently influenced by vascular invasion in tumor surroundings and tumor diameter. The disease-free survival was independently influenced by tumor diameter, necrosis and stage of the disease (pTNM), whereas total survival related to tumor diameter, nodal status, microfocal pattern of tumor growth, vascular invasion and involvement of breast by cancer distant from the tumor mass was independently influenced only by tumor stage (pTNM).