Many clinical trials have shown that expression level differences in NOS2 exist in more than 50% of patients with glioma, breast cancer, prostate cancer, pancreatic cancer, melanoma, liver cancer, cervical cancer, ovarian cancer, nasopharyngeal cancer, lung cancer, stomach cancer, colon cancer, and esophageal cancer [28]. This evidence concerns the gene NOS2 and nasopharyngeal carcinoma.