Introduction. Breast cancer in women is a very common malignant tumor. The prognosis of the development and management of the disease depend on the clinical stage and biological subtype of the tumor. The aim of the research was to study immunohistochemical characteristics of sentinel lymph nodes in various molecular and biological subtypes of breast cancer. Materials and methods. We studied 44 lymph nodes of females with a diagnosed breast cancer using histological and immunohistochemical methods. Regional axillary lymph nodes without signs of metastatic lesions were taken into the investigation. Hematoxylin and eosin staining was performed; monoclonal antibodies to S100 protein and cluster of lymphocyte differentiation 4 and 8 were used. We used light microscopy to assess the results. Results. We determined molecular and biological subtypes of breast cancer. In 45.5% of cases (n=20) women were diagnosed with luminal cancer (Lum); in 25% of cases (n=11), with Her2+ variant; and in 29.5% of cases (n=13), with Tr– cancer (triple-negative). A more pronounced expression of S100-positive cells was observed in the paracortical zone of lymph nodes in triple-negative compared with the luminal one. We revealed uneven distribution of СD8+ lymphocytes in various subtypes of breast cancer, with an increase in their area in the following sequence: Lum (18.6%), Her2+ (19.8%), and Tr– (20.1%). The lowest number of СD4+ lymphocytes was found in the luminal breast cancer. The largest number of CD4+ cells was observed in the Her2+ subtype. Conclusion. The research demonstrated no reliable differences in the reaction of various sub-populations of T-lymphocytes in early-stage breast cancer. At the same time, we revealed a reliable increase in the number of intrafollicular S100+ cells that indicates dendrite cells activation in Tr– cancer. Keywords: breast cancer, immunohistochemistry, regional lymph node, cellular immunity, lymphocytes