HIF1A and nasopharyngeal carcinoma: Specifically, LMP1 was shown to enhance the synthesis of HIF-1α and the expression of HIF-1α-responsive genes in a nasopharyngeal carcinoma (NPC)-derived cell line [31], which could be attributed to enhanced degradation of prolylhydroxylases (PHD) 1 and 3 mediated by SIAH1 [32].