Radiological Features of IDO1 + /PDL1 + Lung Adenocarcinoma: A Retrospective Single-institution Study.

AIM: A combination of immune-checkpoint inhibitors that target the programmed cell death 1 (PD1)/programmed cell-death ligand 1 (PDL1) pathway and indoleamine 2,3-dioxygenase 1 (IDO1) is a promising treatment for non-small-cell lung cancer. Herein, we investigated clinical features of IDO1+ /PDL1+ primary lung adenocarcinoma.

MATERIALS AND METHODS: IDO1 and PDL1 expression in 388 resected primary lung adenocarcinoma samples was evaluated using immunohistochemistry, and the radiological features of patients with IDO1+ /PDL1+ lung adenocarcinoma were analyzed.

RESULTS: Of 388 specimens, 229 (59.0%) were IDO1+ , 131 (33.8%) were PDL1+ , and 109 (28.1%) were IDO1+ /PDL1+ In multivariate analysis, vascular convergence and the absence of surrounding ground glass opacity were significantly associated with IDO1+ /PDL1+ tumors. Fisher's exact test showed high consolidation/tumor ratio was also significantly associated with IDO1+ /PDL1+ tumors. Moreover, maximum standardized uptake in 18 F-fluorodeoxyglucose positron-emission tomography/computed tomography was significantly higher in patients with IDO1+ /PDL1+ tumors than in those with IDO1- or PDL1- tumors.

CONCLUSION: IDO1/PDL1 co-expression was significantly related to radiological invasiveness and malignancy in lung adenocarcinoma. This study may help select patients likely to benefit from combination therapy using immune-checkpoint inhibitors.