PTGS2 and nasopharyngeal carcinoma: For example, polymorphism allele rs5275 in cyclooxygenase-2 (COX-2), rs1024611 in monocyte chemoattractant protein-1 (MCP-1), and rs3216733 in 78-kDa glucose-regulated protein (GRP78) gene promoter are associated with NPC susceptibility [21,22,23].