IDO1 and neoplasm: Upon integrating data on gene expression, tumor mutations and neoantigens from the TCGA CRC cohort, the analysis revealed that the immune checkpoints were significantly hyper-expressed in the group with high FSTL3 expression, including PDL1 (CD274), indoleamine 2,3-dioxygenase 1 (IDO1), CD80, PD1 (PDCD1), T cell immunoreceptor with Ig and ITIM domains (TIGIT) and CD276 (Fig. 1D).