The bioinformatic analysis data were also confirmed, first, by the detected correlation between IDH1 and both the oxidized and reduced glutathione levels in the peritumoral zone and in tumor tissues (Table 3) and, second, by a significant increase of the reduced glutathione level in the group with mutation of the IDH isocitrate dehydrogenase enzyme gene. The gene discussed is IDH1; the disease is neoplasm.