Eleven types of human cancer were incorporated to explore the prognostic value of iNOS for solid tumors, including gastric cancer (GC), breast cancer, pancreatic cancer (PC), colorectal cancer (CRC), hepatocellular carcinoma (HCC), uveal melanoma, ovarian cancer (OC), melanoma, bladder cancer, hypopharyngeal squamous cell carcinoma (HSCC), and laryngeal squamous cell carcinoma (LSCC). This evidence concerns the gene NOS2 and breast cancer.