CD274 and neoplasm: As reported in few studies PD-L1 expression in ONB samples was found to be poor, which translates into a lower chance of response to anti-PD-1/PD-L1 drugs (12), consisted with previous studies, in our study only one (1/15) case expressed PD-L1 (combined positive score (CPS) ≥ 1) in the tumor region.