The specifics of CpG islets methylation of some genes of peripheral blood T-lymphocytes in breast cancer patients before and after treatment

Abstract

Introduction. The growth of primary breast tumor morbidity in the last ten years and increased number of patients with disseminated breast cancer in the Republic of Kazakhstan require the search for methods of early diagnosis of malignant tumors. Determination of breast cancer markers in epigenetic studies allows to use them as diagnostic signs of the presence of malignant tumor and as predictors of treatment effectiveness in patients with this pathology.Aim. To perform a search for therapeutic and prognostic breast cancer markers.Materials and methods. The study included samples of biological material (peripheral blood) of 50 deemed healthy individuals and 103 patients with locally advanced and disseminated breast cancer receiving special therapy. The following methods were used: blood collection, DNA extraction, creation of DNA methylation profiles, sequencing, statistical data analysis.Results. The results of search for epigenetic mutations in peripheral blood of patients with breast cancer showed their role as specific diagnostic, therapeutic and prognostic markers with specificity 0.91 % and sensitivity 0.94 %. The hypothesis on therapeutic significance of identified earlier diagnostic markers in patients with breast cancer, namely hypermethylation of CpG islands associated with genes JAM3, C17orf64, MSC, C7orf51 and CpG island associated with intragene part of chromosome 5 (chr5: 77,208,034–77,329,434) was tested and confirmed.Conclusion. A correlation between DNA methylation characteristics and disease progression during treatment was shown. The study results can be used in clinical practice: epigenetic markers, such as methylation in the CpG islets associated with the JAM3, C17orf64, MSC, C7orf51 genes, and in the CpG islet associated with the intragenic site of chromosome 5 (chr5: 77,208,034–77,329,434) can be used as prognostic markers and therapeutic predictors of breast cancer.