IDO1 and neoplasm: In this retrospective analysis of tumor samples from 29 intestinal and diffuse GCs patients, from patients who underwent primary surgery at Lariboisiere Hospital (Paris, France), we report for the first time, the expression levels of AhR, and of several genes involved in immune gene signature (PD1, PD-L1 and PD-L2) and in tryptophan metabolism (IDO1/IDO2, TDO2).