Gene expression changes of isocitrate dehydrogenase 1 and isocitrate dehydrogenase 2 affect carcinogenesis and survival probability

Isocitrate dehydrogenase (IDH) is an essential metabolic enzyme in the regulation of cellular metabolism. IDH gene encodes three protein isoforms, IDH1, IDH2, and IDH3, and the expression level of isoforms is altered in human cancer types. Examining the gene expression level of IDH is a therapeutic advantage that could help find a new target to use in cancer metabolism. The present study aimed to explore the gene expression level of IDH1 and IDH2 isoforms in the ten common human cancers using bioinformatic tools. In addition, the effect of gene expression changes on IDH1 and IDH2 on carcinogenesis and survival probability was examined in publicly available data deposited in the TCGA database. The results showed that the expression of IDH isoforms showed tissue-specific differences. IDH1 expression increased in esophageal and lung squamous cell carcinoma and lung and stomach adenocarcinoma tumors. Bladder urothelial, breast urothelial, and lung squamous cell carcinoma, colon, and lung adenocarcinoma displayed a significant upregulation of IDH2 expression. There was a direct relationship between the expression of IDH isoforms and the progression of various cancer types. High IDH1 expression led to decreased survival probability in esophageal carcinoma, lung, and stomach adenocarcinoma. Elevated IDH2 expression level led to decreased survival probability in bladder urothelial, breast urothelial, and lung squamous cell carcinoma and colon adenocarcinoma. In conclusion, all data showed that IDH1 could be a biomarker for esophageal carcinoma, lung and stomach adenocarcinoma, and IDH2 for bladder urothelial, breast urothelial, and lung squamous cell carcinoma, and colon adenocarcinoma.