Background: Tumor growth and development is determined by the mutual interaction between the cancer cells themselves and the microenvironment. It contains various elements, including immune cells. Of all, mast cells have one of the most controversial roles. The aim of the present study was to evaluate the expression of mast cell tryptase in the luminal and non-luminal subtypes of breast cancer and establish a possible link between infiltration with MCs and expression of hormone receptors. Material and methods: The experimental study included 80 cases of breast carcinomas that were analyzed immunohistochemically in order to establish the molecular profile and the expression of tryptase, a specific marker of mast cells. The data were processed using the SPSS program. Pearson’s coefficient (r) and the other values were considered statistically significant in case of p≤0.05. Results: Both intratumoral mast cells (MCit) and peritumoral mast cells (MCpt) correlated with the expression of hormone receptors for estrogen (ER) and progesterone (PR). Thus, the following relations were established: MCit and ER (r=0.343, p=0.002), MCpt and ER (r=0.394, p=0.000295) and MCpt and PR (r=0.386, p=0.000409). Statistically significant correlations between HER2 expression and mast cells content have not been established. Conclusions: Mast cells invasion, peri- and intratumoral, is strongly influenced by the expression of hormone receptors. The luminal subtypes of breast cancer are characterized by a higher density of mast cells