Subsequently, we performed immunohistochemical staining to study IL-17D expression in human lung cancer tissues, including 197 NSCLCs (50 squamous cell carcinomas, 124 adenocarcinomas, 12 adenosquamous carcinomas and 11 large cell carcinomas), 13 SCLCs and 68 normal lung tissues. This evidence concerns the gene IL17D and squamous cell carcinoma.