Fig. 1: Upregulated IDO1 protein expression is associated with Immunoscore in CRC.

a Colon tissue was divided into tiles, with tumor tissue highlighted in red and the invasive margin highlighted in green. Scale bars, 1 mm. b The percentages of samples with high, intermediate, or low Immunoscore. c Representative image showing multiplex immunofluorescence staining of two cases of CRC and the CD3⁺ and CD8⁺ TIL identification strategy. Each marker was represented by a different color, as indicated in the panel. White squares indicated the represent image based in the IDO1, CD3, and CD8 marker expression. Scale bars, 100 µm. d Correlation between IDO1 expression and the Immunoscore in 119 human CRC specimens. χ² test (two-sided). e Kaplan–Meier analyses of CRC patients stratified by low versus high levels of IDO1 or the Immunoscore (log-rank test, n = 119). f The relative IDO1 mRNA levels of 119 human CRC specimens related to high, intermediate, or low Immunoscores. g The relative IDO1 mRNA levels of 119 human CRC specimens related to low or high levels of IDO1 protein. h The correlation between IDO protein levels and IDO1 mRNA expression, according to Spearman correlation analysis (two-sided), R² = 0.004, P = 0.8218. i Western blotting analysis and quantification of IDO in the indicated cells. The relative mRNA expression of IDO1 in the indicated cells. In i, error bars represent the mean ± SD of three independent experiments. ns not significant, two-sided Student’s t-test. Source data are provided as a Source Data file.