Immunohistochemical expression of the mammalian target of rapamycin pathway in penile squamous cell carcinomas: a tissue microarray study of 112 cases

AIMS: The aim of this study was to evaluate the immunohistochemical expression of mammalian target of rapamycin (mTOR) pathway-related biomarkers in penile carcinomas, and to assess associations with histological type, histological grade, and human papillomavirus (HPV) infection.; METHODS AND RESULTS: We built four tissue microarrays from 112 invasive penile squamous cell carcinomas, and evaluated the immunohistochemical expression of PTEN, phospho-AKT, phospho-mTOR, and phospho-S6. We found decreased or loss of PTEN expression in 87% of cases. Warty and/or basaloid carcinomas had a higher proportion of PTEN loss (P=0.02), whereas keratinizing tumours showed higher levels of phospho-S6 (P=0.009); phospho-AKT and phospho-mTOR levels were not significantly different between warty/basaloid and keratinizing carcinomas (P=0.75 and P=0.77, respectively). PTEN was not associated with histological grade (P=0.18). Expression levels of phospho-S6 were significantly higher in low-grade tumours (P=0.001), whereas expression levels of phospho-AKT and phospho-mTOR were slightly higher in high-grade tumours (P=0.01 and P=0.35, respectively). We did not find any association between HPV infection and mTOR markers (P≥0.2 in all cases).; CONCLUSIONS: Our results provide evidence of dysregulation of the mTOR pathway in penile carcinomas independently of HPV infection. Future clinical studies should further evaluate the prognostic and predictive usefulness of these markers in patients with penile cancer. © 2013 John Wiley & Sons Ltd

The epidermal growth factor receptor is frequently overexpressed in penile squamous cell carcinomas: a tissue microarray and digital image analysis study of 112 cases

Disseminated penile cancer is usually treated with chemotherapy. However, response rates are far from acceptable. Recently, anti-epidermal growth factor receptor (EGFR) monoclonal antibodies have shown to be clinically useful in penile carcinomas. Nevertheless, only a few cases of penile carcinomas have been evaluated for EGFR expression. In this study, we assessed the immunohistochemical expression of EGFR in 112 patients with penile squamous cell carcinoma. We built 4 tissue microarrays and evaluated EGFR expression using a monoclonal mouse anti-EGFR antibody. For digital image analysis, we used the open-source software ImageJ version 1.47 (NIH, Bethesda, MD) along with the immunomembrane plug-in. Membranous EGFR expression was evaluated, taking into account staining completeness (0-10 points) and staining intensity (0-10 points) for a combined score (0-20 points). We classified the cases as follows: negative EGFR expression, 0 to 3 points; low EGFR expression, 4 to 8 points; and high EGFR expression, 9 to 20 points. The distribution of EGFR immunohistochemical expression was as follows: 13 cases (12%) were EGFR negative, 49 cases (44%) had low EGFR expression, and 50 cases (44%) had high EGFR expression. EGFR expression was not associated with histologic subtype (P = .47), histologic grade (P = .77), or human papillomavirus status (P = .14). In conclusion, immunohistochemical EGFR expression appears to be a common feature of penile carcinomas, independently of histologic subtype, histologic grade, and human papillomavirus presence. Whether or not EGFR expression is associated with EGFR gene mutation or if it can be used to predict response to therapy in patients with disseminated penile cancer should be evaluated in future studies. © 2013