CXCL9 and nasopharyngeal carcinoma: Based on a multiplex suspension array system, a previous study found that CXCL9 expression is significantly up-regulated in patients with NPC and oral cavity squamous cell carcinoma.31, 32 Quantitative real-time PCR and immunohistochemistry suggested that up-regulated CXCL9 is related to the aggressiveness of NPC, and an enzyme-linked immunosorbent assay indicated that its serum level may be a valuable prognostic indicator.33