RESUMEN
OBJECTIVE: It has been demonstrated that IDO1, a target of immune checkpoint inhibition, functions as an oncogene in the majority of human malignancies. IDO1's function in human pan-cancers hasn't been thoroughly studied, though. MATERIALS AND METHODS: The Kaplan-Meier (K-M) and COX analyses were applied to the survival analysis. Furthermore, we used Spearman's correlation analysis to examine the associations between IDO1 and microsatellite instability (MSI), DNA methyltransferases (DNMTs), tumor mutational burden (TMB), the associated genes of mismatch repair (MMR), and immune checkpoint biomarkers. Moreover, immunohistochemical analysis and qRT-PCR were used to evaluate IDO1's expression in pan-cancer cells. RESULTS: The findings of this study reveal that IDO1 has abnormal expression in a number of malignancies and is related to the prognosis for UVM, LGG, KIRP, GBM, LAML, OV, READ, MESO, SARC, SKCM, and HNSC. Furthermore, the aberrant IDO1 expression was connected to the TMB, MSI, MMR, drug sensitivity, immune cells infiltrating, and tumor immune microenvironment across a variety of cancer types. The PCR results showed that in contrast to normal cells, IDO1 was found to be significantly highly expressed in breast cancer cells and hepatocellular carcinoma cells, and significantly lowly expressed in gastric cancer cells. CONCLUSION: The clinical treatment of IDO1 is now better supported by a theoretical basis and guidelines provided by our study.