IFNG and squamous cell carcinoma of penis: Immunohistochemistry (IHC) analysis of eight cytokines (IL-1A, IL-1B, IL-2, IL-6, IL-12, TGF-β1, TNF-α and IFN-γ) was performed in paired tumour tissues and corresponding negative surgical margins from 94 patients with penile squamous cell carcinoma.