IDO1 and intestinal neoplasm: When the analysis was performed for intestinal neoplasm samples, there was no correlation in the change in IDO1 expression vs. KYNU (slope = 0.10; R2 = 0.04), HCAR3 (slope = 0.37; R2 = 0.09), IL4I1 (slope = 0.35; R2 = 0.24), KMO (slope = 0.24; R2 = 0.11), nor TDO2 (slope = 0.70; R2 = 0.21) (Supplementary Figure S1).