The objective: determining gene polymorphism features ERS1, CYP2D6 in patients with breast cancer (RHZ) and endometrial cancer (EC) and the impact assessment studied genetic characteristics compared to receptor status (immunohistochemical determination of expression levels of ER, PR) tumors and the results of the treatment. Patients and methods. article presents the results of complex clinical, morphological, clinical-genealogical, and molecular-genetic examination of 28 females: 19 patients with breast cancer (BC), 9 patients with endometrial cancer (EC), including 5 patients with primary-multiple tumors (PMT) with and without tumor pathology aggregation in families. Results. The It was determined that in patients’ families malignant tumors of breast, uterine body and/or ovaries prevail that corresponds to Lynch type II syndrome (family cancer syndrome). Molecular-genetic examination of genomic DNA of peripheral blood and histological sections for the presence of SNPs of ESR and CYP2D6*4 genes comparing with the results of immunohistochemical study of tumors for receptors ER and PR status have not found associations between these characteristics; although among EC patients the occurrence of genotypes 397ТТ and 351АА was significantly higher comparing with BC patients (55.55% and 10.5% for genotype 397ТТ,and 15.8% for genotype 351АА, respectively). At the same time the patients with BC and primary-multiple tumors (PMT) of female reproductive system organs (FRSO) that carried mutations in BRCA1 in all the cases demonstrated positive ER and PR receptor status and adverse combinations of polymorphous variants of the genes ESR1 (397СС, 397ТС) and CYP2D6*4 (1846G, 1846GA), suggesting combined effect of these factors on the development of malignant neoplasias of FRSO in families with positive family cancer history. In BC patients, receiving standard hormone therapy with tamoxifen, those, who had genotype 1846GG of the gene CYP2D6*4, in 3 patients (15.8%) of 19 (100%) patients disease recurrence was diagnosed. Conclusion. The obtained results allow clinical use of the assessment of polymorphism frequency of the genes ESR1 and CYP2D6*4 for selection of individual hormone therapy regimens schemes for BC patients, to increase efficacy of dispensary observation after finishing of special therapy for such patients, and also personalization of complex and combined treatment regimens. Key words: breast cancer, endometrial cancer, family cancer syndrome, single nucleotide polymorphisms (SNPs) of the genes ESR1, CYP2D6*4.
