Бюллетень сибирской медицины (Jan 2021)
Redox forms of glutathione in malignant lesions of the stomach with varying aggressiveness degrees
Abstract
Aim. To study the levels of reduced and oxidized glutathione (GSH and GSSG, respectively), as well as the thiol status in gastric cancer (GC) tumors of various histological types and grades.Materials and methods. The indicators were determined by ELISA methods in tumor, peritumoral and visually intact tissues obtained during surgery from 52 patients with GC: 18 patients had a G1-2 adenocarcinoma (AC), 8 with G3 AC, 6 with signet ring cell cancer (SRCC), 14 with combined gastric lesions (CGL) – AC with signet ring cell fragments, 6 with patients with a component of undifferentiated cancer, G4.Results. In the groups of patients with low-differentiated and undifferentiated tumors, the GSH content in the tumor tissue and the peritumoral zone was higher than in the group of patients with well- and moderately-differentiated tumors. Tumor GSH levels in G3 AC and SRCC exceeded the values in visually intact tissues. Moreover, in the visually intact tissue of patients with SRCC, GSH level was reduced relative to G1-2 AC and CGL. GSH in all tissues of patients with CGL was higher than in patients with G1-2 AC. The lowest level of GSSG in the tumor tissue was registered in SRCC: 27.5% lower than in G1-2 AC and 30.3% lower than in G3 AC. Patients with undifferentiated tumors (G4 AC) had the highest GSH content in all studied tissues: by 29.9% in tumor; by 40.7% in peritumoral zone; and in visually intact tissue not only GSH, but also GSSG was increased by 22.5–25.5% in comparison with AC G1-2. G4 AC was also characterized by a sharp increase in the thiol status in tumor tissues by 80.2 and 89.9% higher than in visually intact and peritumoral tissues, and it was statistically higher than in AC G1-2, AC G3, SRCC and CGL. The ratio of GSH and GSSG was the most informative.Conclusion. Poor AC differentiation (in the row G1-2, G3, G4) and a change of histological tumor type (AC, SPL and SRCC), i.e. an increase in tumor aggressiveness, were accompanied by the enhancement of reductive processes in tumor tissue, as evidenced by the statistically significant increase in the GSH/GSSG coefficient and a sharp increase in the thiol status in G4 AC.
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