IDO1 and neoplasm: Analysis of total RNA and genes that were substantially different between the patient groups in 50 pretreatment tumor biopsies revealed at least a 2.5-fold increase in the expression of 22 immune-related genes in clinically active patients, including cytotoxic T cell markers (e.g., CD8A, perforin 1, granzyme B), Th1 cytokines or chemokines, MHC-II, and other immune-related genes (e.g., NKG7, IDO1) [81].