RESEARCH OF ONCOLOGICAL RISK MECHA-NISMS IN PATIENTS WITH TYPE 2 DIABETES

The aim of the study was to investigate the mechanisms of forming of oncological risk in patients with diabetes mellitus (DM) type 2 by determining the dependence of content of phosphorylated PRAS40 (phospho-PRAS40) from levels of insulin and IGF-1. Material and methods of the research. 88 pa-tients were investigated and were divided into groups: I – healthy (control group) (n = 14); II – patients with DM type 2 (n = 26); III – patients with cancer without DM (n = 24); IV - with a combination of cancer and diabetes (n = 24). The therapy of the patients with DM of the II and the IV group included different combinations of antidia-betic pills and insulin. The level of phospho-PRAS40 in peripheral blood mononuclear cells (PBMC) was determined by enzyme-linked immunosorbent assay (ELISA) using a diagnostic kit ELISA KNO0421 (Invitrogen, USA). Insu-lin and IGF-1 levels were determined on a Stat fax 303+ automatic analyser (US) using diagnostic kits Insulin ELISA, EIA-2935 and IGF-1 600 ELISA, EIA-4140 (DRG, Germany). Compensation of DM was assessed by the HbA1c level, determined on the BIO-RAD D-10 automatic analyser (USA). Data analysis was performed using Statistica 12.0 (StatSoft Inc., USA). Differences between values in control and experimental groups were determined using One-Way-ANOVA and Student's t test. The differences were considered significant at P <0.05. Results of research. Obesity was detected in pa-tients with type 2 DM of group II as well as in women of groups III and IV with breast and endometrial cancer, in patients with pancreatic cancer obesity was not detected. The average duration of diabetes in patients with breast and endometrial cancer was higher than in patients with pancreatic cancer (P < 0.05). Significant hyperinsuline-mia was detected in patients of group II with type 2 DM and in patients of groups III and IV in women with breast cancer (P < 0.05) and endometrial cancer (P < 0.05), in patients with pancreatic cancer no hyperinsulinemia was detected (P > 0.05). Increased levels of IGF-1 were detected in patients in groups II (P < 0.05), III (regardless of cancer localization) (P < 0.05) and IV in patients with breast and endometrial cancer (P < 0.05). Significantly higher phospho-PRAS40 levels were found in patients with type 2 DM and in patients of group III with breast and endometrial cancer (P < 0.05) compared to the control group. Phospho-PRAS40 levels were significantly lower in the examined patients of group IV, regardless of the forms of cancer (P < 0.05). According to the level of HbA1c, 13.3% of patients in group II had compensated diabetes, 23.3% had subcompensated, 53.4% - decompensated. In group IV compensated DM was detected in 5.0%, subcompensated in 20.0%, decompensated in 75.0% of patients. Conclusions. Obesity, hyperinsulinemia and in-creased levels of IGF-1 are factors of the activation of the PI3K/Akt/mTOR signalling pathway and mechanisms of oncogenesis in patients with type 2 DM. Phosphorylation of PRAS40 reflects activation of the PI3K/Akt/mTOR signalling pathway and may indicate a predisposition of women with type 2 diabetes to breast and endometrial cancer. Pancreatic cancer in patients with diabetes with the duration of up to 3 years that is not associated with obesity and hyperinsulinemia may be a manifestation of secondary type 3c diabetes mellitus (T3cDM), which is caused by the oncological process in the pancreas.