CD274 and nasopharyngeal carcinoma: For instance, PD-L1 is expressed at remarkably higher levels in the EBV-positive NPC cell line C666-1 (RRID: CVCL_7949) compared to the EBV-negative cell line NPC-TW03 (RRID: CVCL_6010), or the pre-malignant nasopharyngeal cells NP69SV40T (RRID: CVCL_F755).