Parameters of the glutathione system and thioredoxin in blood plasma and ascites and GSTP1 Ile105Val gene polymorphism as factors of resistance to platinum-containing chemotherapy in ovarian cancer patients

Background. Chemotherapy is one of the main types of treatment in ovarian cancer. Standard first-line treatment includes platinum drugs. Every fifth patient develops chemoresistance after platinum-containing first line therapy. Glutathione detoxification systems play an important role in platinum drugs utilization.Purpose. To assess the redox status of blood plasma and ascitic fluid in ovarian cancer patients before and after neoadjuvant platinum-containing chemotherapy (NACT).Materials and methods. We determined the activity of the glutathione system and thioredoxin levels in bloodplasma before and after NACT and in the ascitic fluid before NACT, and the presence of GSTP1 gene polymorphism (Ile105Val (rs1695), Ala114Val (rs1138272) in 30 III–IV FIGO stage ovarian cancer patients. Patients were divided into 3 groups: NR – no relapse in 2 years after last chemotherapy course; R1 – relapse in less than 6 months; R2 – relapse in more than 6 months.Results. We established an increase of the glutathione-transferase activity and a decrease of the GSH level inplasma after chemotherapy in R1 patients, and an opposite dynamic of glutathione-transferase and GSH in the R2 group. Thioredoxin level in plasma of all patients was lower than in the control group; differences in levels between groups were not statistically significant. GSTP1 105Val allele was more frequently present in patients than in the control group, and more frequently in R2 than in R1.Conclusion. The increase in plasma glutathione-transferase and glutathione-reductase levels can be a prognostic marker of early relapse. Thioredoxine dynamics do not correlate with the chemotherapy response. The presence of the GSTP1 105Val allele is a risk factor for ovarian cancer development, but a protective factor against early relapse.