In the LDH cytotoxicity analysis, the cytotoxic activitity of NK cells against NPC cell lines (C666-1 or 5-8F) with lenti-ULBP4 was significantly increased as compared to those with lenti-vector at the three E/T ratios (10:1, 20:1, and 40:1), respectively (all P <0.05, Figure 4E and 4F). Here, RAET1E is linked to nasopharyngeal carcinoma.