Intratumoural Effector Cell Subpopulations in Breast Cancer: a Literature Review and Own Data Report

Breast cancer (BC) is most prevalent female malignancy worldwide. Despite advances in BC diagnosis and progress in drug therapy, a series of challenges associated with emergent tumour resistance causing the disease escalation still remain. Immune evasion is among the driving forces of tumour resistance against modern treatments, which promotes world-active research into the mechanisms of tumour—immune interaction.Tumour microenvironment is known to contribute greatly to the nature of this interaction. Immune cells are constitutive of tumour microenvironment as tumour-associated macrophages, myeloid-derived suppressor cells and tumour-infi ltrating lymphocytes. Tumour-infi ltrating lymphocytes are represented by B-, T- and NK-cells, which localisation and subpopulation structure in tumour may possess a prognostic and clinical significance. Th e infi ltration density by certain effector cell types prior to chemotherapy is an important predictor of patient survival. Putting otherwise, the presence of effector lymphocyte subpopulations in tumour defi nes the strength of antitumour immunity and may establish the success of drug treatment.This study analysed the infiltration levels of CD3, CD4, CD20 and CD38 lymphocytes in several molecular BC subtypes. Tumour immunophenotyping was performed in cryosectioning and immunofl uorescence assays with a ZEISS AXIOSKOP microscope, Germany. We analysed 96 luminal BC (37 subtype A (38.5 %), 52 B-Her2-negative subtype (54.2 %), 7 B-Her2-positive subtype (7.3 %)) and non-luminal BC samples (3 HER2+ subtype (14.3 %), 18 triple-negative subtype (85.7 %)). The infiltration and antigen expression patterns have been assessed. Analyses of tumour-infi ltrating subpopulations revealed lower infiltration in luminal BC vs. other subtypes, albeit at no significance.