MOLECULAR-GENETIC PHENOTYPES OF BREAST CANCER, THEIR PROLIFERATIVE ACTIVITY, DEGREE OF SPREADING AND DIFFERENTIATION IN PATIENTS WHICH WERE SUFFERED BY THE ACCIDENT AT ChNPP.

Objective: analysis of molecular genetic phenotypes, their proliferative activity, degree of spread and differentiation of tumors in breast cancer patients affected by the accident at the Chornobyl Nuclear Power Plant.

Materials and methods: 96 breast cancer patients who were exposed to ionizing radiation as a result of the accident at the Chornobyl Nuclear Power Plant were examined. Clinical, radiological, instrumental, morphological,immunohistochemical research methods were used.

Results and conclusions: In patients who have been exposed to radiation, the frequency with which the moleculargenetic phenotypes of breast cancer occur is somewhat different from the generally known data. Thus, luminal Aphenotype was diagnosed in 17.7 %, luminal B in 56.2 %, HER2/neu expressing in 6.2 % and triple negative (TN)phenotype in 19.8 % patients. Proliferative activity indicators on average in patients with luminal A phenotype wereat the level of 12.7 %, luminal B - 41.5 %, triple negative - 55.6 %, and HER2/neu positive breast cancer - 32.5 %.Patients with different molecular genetic phenotypes are diagnosed with different prevalence values of the TNM criteria. Metastatic lesions of regional lymph nodes (LNs) were diagnosed in 97.9 % of patients belonging to all phenotypes of breast cancer. Ki-67 values that did not exceed 20 % were found in 22.9 % of patients, the main number -17.7 % had the luminal A subtype. In 77.1 % of patients, Ki-67 values were beyond 20 %, which indicates a moreaggressive course of the disease in the majority of patients, which included patients with various molecular genetic subtypes, except for luminal A. A high degree of differentiation of mammary gland tumors was diagnosed in 8.3% of patients. The main number of them, 6.2 %, had the luminal A phenotype. A moderate degree of differentiationwas found in 65.6 %, where 43.7 % of patients had a luminal B HER2/neu negative phenotype. A low degree of differentiation was diagnosed in 26 % of patients, among whom 12.5 % were diagnosed with TN, and 9.4 % had a luminal B HER2/neu negative phenotype.