In conclusion, our results suggest that hypoxia-induced suppression of UPF1 expression decreases NMD efficiency, leading to the stabilization of COX-2 and PD-L1 mRNAs, thus activating the p38/MAPK and JAK2/STAT3 pathways and promoting tumor progression in NPC cells. The gene discussed is CD274; the disease is nasopharyngeal carcinoma.