IL-12 as a Potential Prognostic Marker in Penile Cancer: Implications for Immune Dysregulation

Penile cancer (PeCa) is a rare malignancy with few validated tissue biomarkers to guide prognosis and treatment, despite growing evidence for a key role of inflammation in its biology. This retrospective study evaluated whether the immuno-expression of selected pro-inflammatory cytokines is associated with disease progression and cancer-specific survival (CSS) in PeCa. 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. Compared with surgical margins, tumour tissues showed a characteristic inflammatory shift, with markedly increased IL-1β and IL-6 and relatively reduced TNF-α, IFN-γ, IL-12 and IL-2. Receiver Operating Characteristic (ROC) analysis indicated that TNF-α, IL-6 and IL-12 had the strongest ability to discriminate tumour from normal tissue and provided data-driven cut-offs for subsequent analyses. Within tumour samples, high IL-1α, IL-12 and TGF-β1 immuno-expression was significantly associated with advanced UICC TNM prognostic stage and lymph node involvement. Importantly, in contrast to the classically anti-tumour role of IL-12 described in many other solid cancers, increased IL-12 immuno-expression in tumour tissues in our cohort was independently associated with poorer CSS in multivariable Cox regression (HR 2.42, 95% CI: 1.08-5.41, <i>p</i> = 0.031), alongside advanced TNM stage (HR 5.03, 95% CI: 2.12-11.95, <i>p</i> = 0.0002). These findings highlight IL-1α, IL-12 and TGF-β1 as promising tissue biomarkers of aggressive PeCa and support a central role for cytokine-driven immune dysregulation in penile cancer. The prognostic value of IL-12 should be considered exploratory and warrants validation in larger, multicentre cohorts.