Pro-Inflammatory Cytokine Gene Expression in Penile Cancer: Preliminary Studies

Abstract

Background and Objectives: Penile cancer is a rare neoplasm in developed countries with an incidence of 0.8/100,000 per male inhabitant. Despite the development of personalized medicine and multimodal treatment, the outcome of penile cancer treatment is insufficient. Our study aimed to assess the levels of pro-inflammatory cytokines' mRNA such as interleukin 1-A (encoded by IL1A gene, alias IL-1A), interleukin 1-B (IL1B, IL-1B), interleukin 1 receptor antagonist (IL1RN, IL-1RN), interleukin 6 (IL6, IL-6), transforming growth factor β1 (TGFB1, TGFβ-1), and Interferon-gamma (INFG, INF-γ) in penile cancer tissue and associate them with tumor progression and patient survival. Material and Methods: Skin biopsies from patients suffering from penile cancer (n = 6) and unchanged foreskin from 13 healthy adult males undergoing circumcision due to a short frenulum were obtained. Pro-inflammatory cytokine mRNA levels were quantified through qPCR. Results: We observed higher expression of pro-inflammatory cytokine genes (IL-1A, IL-1B, IL-6, INF-γ, TGF-β) in penile cancer tissue. The average follow-up period was 48 months (range: 38-54 months), during which only one penile tumor progression was observed However, this was without association with the nature of tumor (patient refused radical treatment). Conclusions: This is the first study to show increased expression of cytokines such as IL-1A, IL-1B, IL-6, INF-γ, and TGF-β in penile cancer with positive correlation between TNM staging and INF-γ levels in tumor samples (rs = 0.672, p = 0.045), which may be associated with the immunosuppressive role of the tumor environment.

Keywords: IFN-γ; IL-1; IL-1RN; IL-6; TGF-β1; penile cancer.

Figure 1

Cytokine gene expression at the mRNA level in penile tissue. Gene expression was assessed as described in the Materials and Methods section. The ordinate axis is divided into three sections to show all important values. Bars and whiskers represent the mean ± standard deviation of the mean (SEM) of cancer tissues (bars with chessboard pattern) normalized to control foreskin samples (gray bars), counted as 1, shown as a dotted horizontal line. * p < 0.05, *** p < 0.001 (Mann–Whitney U test between each group, Kruskal–Wallis ANOVA test between all groups, upper dotted line). Abbreviations: ca penis, penile cancer.

Figure 2

Correlation plots of cytokine levels in tumor samples and clinical data. The ordinate axes are shown on a logarithmic scale. Selected dots represent expression data normalized to control tissues (n = 1), while other values are represented on horizontal axes. Solid color lines represent linear regression curves with 95% confidence band (dotted lines). (A–C) represent clinical data (age, (A), BMI, (C)) or values before surgery (CRP, (B)), while pTNM (D) stages are coded: carcinoma planoepitheliale veruccosum; 1 TiS; 2 pT1aNxMx; 3 pT2N0Mx; 4; (E) represents histological G grading.