MDH1 and testicular germ cell tumor: By comparing the differential methylation between cancerous and non-cancerous samples in the UALCAN database (Supplementary Figure S4A), we observed a correlation between higher MDH1 expression levels in LUAD, BLCA, thyroid carcinoma (THCA), and testicular germ cell tumors (TGCT) and reduced methylation levels (Supplementary Figure S4A).