Aberrant expression of Mas and iNOS in nasopharyngeal carcinoma and the clinical significance: an immunohistochemistry study

As an upstream activator for inducible nitric oxide synthase (iNOS), Mas has been reported to be upregulated in several cancers. However, its role in human nasopharyngeal carcinoma (NPC) is still unclear. In this study, we performed the immunohistochemistry to detect the expression of Mas and iNOS in 115 cases of NPC and 30 cases of normal nasopharyngeal tissues, and investigated the relationship between these biomarkers and the relevant clinicopathological parameters. Mas expression in NPC tissues was significantly higher than that in normal nasopharyngeal tissues (P = 0.001). Overexpression of Mas was prominently related to lymphatic metastasis (P = 0.001) and advanced clinical stage (P = 0.039). Besides, the relative level of iNOS in NPC tissues was obviously higher than its expression in normal tissues (P < 0.001). High-level iNOS expression was also associated with older age (P = 0.005), lymphatic metastasis (P = 0.010) and advanced clinical stage (P = 0.003). Moreover, the result of spearman correlation test showed a significant positive relationship between Mas and iNOS (r = 0.300, P < 0.001). In ROC analysis, the confederative marker that combining Mas and iNOS had a more potent and efficient diagnostic value for NPC than either single makers (AUC = 0.782, 95% CI: 0.691-0.873, P < 0.001), which indicated the potential application of Mas and iNOS in clinical practice for screening and diagnosing metastatic nasopharyngeal carcinoma. In conclusion, Mas and iNOS are closely related to the carcinogenesis and development of NPC, indicating that these biomarkers could be served as potential prognostic indicators for NPC patients.