CD274 and nasopharyngeal carcinoma: All previous studies on the clinical significance of PD-L1 expression in NPC evaluated the TCs [8,19,20,21,22,23,24,25,26,27,28], but only three of them (using clone D3, SP142 and E1L3N, respectively) also assessed the PD-L1 expression on ICs [8,19,28].