IDO1 and non-small cell lung carcinoma: We recently found that among 116 NSCLC patients, changes in IDO metabolites levels after treatment predicted treatment outcomes [90]: (1) Baseline IDO activity was predictive of OS, and higher IDO activity was associated with a higher risk of distant metastasis and shorter survival time; (2) the ratio of kynurenine after/before radiotherapy could be used as biomarker for immune status during radiotherapy.