Histological and immunohistochemical features of medullary breast cancer.

Disputes take place among many scientists about the position of MC in the classification of breast cancer. Some say that this kind of tumor is a sign of invasive ductal carcinoma (IDC). Instead, most of modern researchers distinguish MC of the breast as a separate nosological unit. Primarily there were selected 20 cases of MC and 10 cases of IDC (as control group). The immunohistochemical study revealed the presence of ER, PR, HER2/neo, p53, Ki-67, MMP1 and E-cadherin receptors. In the study of receptor status of tumors it was observed that 100% of MC cases were estrogen-, progesterone- and HER2/ neu negative. The status of tumors on receptor p53 and Ki-67 was as follows: p53+ status had 80% and Ki-67+ had 85% of tissues of MC. In 75% of cases MC cells expressed marker of adhesion and in 100% of cases cells were receptor-negative for expression of MMP1. The data of the study show that the invasive ductal carcinoma and medullary carcinoma are completely independent and different types of malignancy in the breast. The favorable behavior of medullary cancer is associated with expression of E-cadherin receptors, which are essentially adhesion factor and absence of MMP1 which are factors of metastatic potential of the tumor.