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PREDICTORS OF CHEMORESISTANCE TO PLATINUM-CONTAINING NEOADJUVANT CHEMOTHERAPY IN ADVANCED OVARIAN CANCER

Chemoresistance is one of the main causes of treatment failure in advanced ovarian cancer (OC). In order to identify predictors of chemoresistance, 30 patients with ascitic form of OC, who received neoadjuvant chemotherapy (NACT) according to AP regimen, were examined. In the epithelial cells of ascites and in tumor tissue after NACT, expression of the VEGFa, ABCB1 and ERCC1 genes was assessed by PCR-RT. The effectiveness of NACT was assessed using the criteria of therapeutic pathomorphosis, survival - using the Kaplan-Meier criterion, the relationship of clinical and molecular parameters - using the Mann-Whitney criterion. Results. We established that in 43% of patients the response to NACT was absent (CRS1), the significant response (CRS2) was in 35% of cases, and the complete response (CRS3) was in 21% of cases. VEGFa expression was increased in ascites in 17% of cases, in tumor tissue - in 33% in the CRS1 group. In groups with CRS 2,3, overexpression of VEGFa in ascites was detected in 25% of cases, in tumor tissue in 37.5%. ABCB1 mRNA expression was increased after NACT in 50% of cases in the CRS1 group and in 25% of cases in the CRS 2,3 group. Thus, platinum-based NACT initiates an increase in the expression of VEGFa and ABCB1 in tumor tissue. We established that in case of high expression (ERCC + / VEGF + / ABCB1 +) in ascites, there is a statistically significant increase in relapse-free survival compared with the group with low or absent expression (p = 0.012). The overall survival rate was 41.8 months in patients with overexpression of the studied genes in the tissue of the primary tumor after NACT and 25.3 months in patients with low expression (p = 0.058). Conclusion. The levels of ERCC1, VEGFa and ABCB1 mRNA in ascitic cells before NACT and in the primary tumor after NACT according to the AP scheme can serve as a predictor of the effectiveness of this treatment in ascitic OC.