Charakterisierung des EGF-Rezeptorstatus beim Peniskarzinom

Genomic profiling reveals the pivotal role of hrHPV driving copy number and gene expression alterations, including mRNA downregulation of TP53 and RB1 in penile cancer

The incidence of penile cancer (PeCa) is increasing worldwide, however, the highest rates are reported in underdeveloped countries. The molecular mechanisms that underly the onset and progression of these tumors are still unclear. Therefore, our goal was to determine the genome-wide copy number alterations and the involvement of human papiloma virus (HPV) (TP53 and RB1), inflammatory (COX2 and EGFR), and PI3K/AKT pathway (AKT1, AKT2, EGFR, ERBB3, ERBB4, PIK3CA, and PTEN) associated genes in patients with PeCa from a high incidence region in Brazil (Maranhão). HPV genotyping was performed by nest-PCR and genome sequencing, copy number alterations (CNAs) by array comparative genomic hybridization and gene copy number status, gene, and protein expression by quantitative polymerase chain reaction, reverse transcriptase-quantitative polymerase chain reaction, and immunohistochemistry, respectively. HPV genotyping revealed one of the highest frequencies of HPV reported in PeCa, affecting 96.4% of the cases. The most common CNAs observed were located at the HPV integration sites, such as 2p12-p11.2 and 14q32.33, where ADAM 6, KIAA0125, LINC00226, LINC00221, and miR7641-2, are mapped. Increased copy number of ERBB3 and EGFR genes were observed in association with COX2 and EGFR overexpression, reinforcing the role of the inflammatory pathway in PeCa, and suggesting anti-EGFR and anti-COX2 inhibitors as promising therapies for PeCa. Additionally, TP53 and RB1 messenger RNA downregulation was observed, suggesting the occurrence of other mechanisms for repression of these oncoproteins, in addition to the canonical HPV/TP53/RB1 signaling pathway. Our data reinforce the role of epigenetic events in abnormal gene expression in HPV-associated carcinomas and suggest the pivotal role of HPV driving CNAs and controlling gene expression in PeCa.

Identification of somatic gene mutations in penile squamous cell carcinoma

There is a lack of studies on somatic gene mutations and cell signaling driving penile carcinogenesis. Our objective was to analyze somatic mutations in genes downstream of EGFR in penile squamous cell carcinomas, especially the mTOR and RAS/MAPK pathways. We retrospectively analyzed somatic mutations in 10 in situ and 65 invasive penile squamous cell carcinomas by using Sequenom's Mass Spectrometry iPlex Technology and Oncocarta v1.0 Panel. The DNA was extracted from FFPE blocks and we identified somatic missense mutations in three in situ tumors and in 19 invasive tumors, mostly in PIK3CA, KRAS, HRAS, NRAS, and PDGFA genes. Somatic mutations in the PIK3CA gene or RAS family genes were neither associated with tumor grade, stage or outcome, and were equally often identified in hrHPV positive and in hrHPV negative tumors that showed no p53 expression. Mutations in PIK3CA, KRAS, and HRAS are frequent in penile squamous cell carcinoma and likely play a role in the development of p53-negative tumors. Although the presence of these mutations does not seem to correlate with tumoral behavior or outcome, they could be biomarkers of treatment failure with anti-EGFR mAb in patients with penile squamous cell carcinoma.

Epidermal growth factor receptor-targeted therapy in locally advanced or metastatic squamous cell carcinoma of the penis

OBJECTIVE

To evaluate the safety and efficacy of epidermal growth factor receptor (EGFR)-targeted therapy in patients with advanced penile or scrotal cancer.

PATIENTS AND METHODS

We retrospectively reviewed the charts of patients with penile or scrotal squamous cell carcinoma who had visited our tertiary cancer centre between 2002 and 2009, including their subsequent treatment and follow-up. We collected details of EGFR-targeted therapy and clinical outcomes. Treatment-associated time-to-disease-progression (TTP), overall survival (OS), responses to therapy and toxicity were evaluated.

RESULTS

A total of 24 patients had received EGFR-targeted therapies, including cetuximab, erlotinib and gefitinib. The most common treatment given (to 67% of patients) was cetuximab combined with one or more cytotoxic drugs. The most common adverse effect was skin rash (71%). The median (range) TTP and OS were 11.3 (1-40) and 29.6 (2-205) weeks, respectively. The OS time for patients with visceral or bone metastases was significantly shorter than it was for those without (24.7 vs 49.9 weeks, P = 0.013). Among 17 patients treated with cetuximab alone or in combination with cisplatin, there were four partial responses (23.5%) including two patients with apparently chemotherapy-resistant tumours.

CONCLUSIONS

Our results suggest that cetuximab has antitumour activity in metastatic penile cancer, and may enhance the effect of cisplatin-based chemotherapy. Prospective studies of EGFR-targeted therapies in men with these tumours are warranted.

Molecular research in penile cancer-lessons learned from the past and bright horizons of the future?

Penile cancer is a rare tumor. There is a limited understanding of the biological mediators of prognostic and therapeutic importance in penile cancer. However, there exists some fundamental understanding of the major pathways involved in the development of penile pre-neoplastic lesions and neoplasms. The aim of the present review is to highlight our current state of molecular knowledge in penile cancer to foster the necessary tools for researchers to pave major advancements in our current treatment paradigms and cancer specific outcomes.

Epidermal growth factor receptor (EGFR)-RAS signaling pathway in penile squamous cell carcinoma

Penile Squamous Cell Carcinoma (SCC) is a rare cancer with poor prognosis and limited response to conventional chemotherapy. The genetic and epigenetic alterations of Epidermal Growth Factor Receptor (EGFR)-RAS-RAF signaling in penile SCC are unclear. This study aims to investigate four key members of this pathway in penile SCC. We examined the expression of EGFR and RAS-association domain family 1 A (RASSF1A) as well as the mutation status of K-RAS and BRAF in 150 cases of penile SCC. EGFR and RASSF1A expression was evaluated by immunohistochemistry. KRAS mutations at codons 12 and 13, and the BRAF mutation at codon 600 were analyzed on DNA isolated from formalin fixed paraffin embedded tissues by direct genomic sequencing. EGFR expression was positive in all specimens, and its over-expression rate was 92%. RASSF1A expression rate was only 3.42%. Significant correlation was not found between the expression of EGFR or RASSF1A and tumor grade, pT stage or lymph node metastases. The detection of KRAS and BRAF mutations analysis was performed in 94 and 83 tumor tissues, respectively. We found KRAS mutation in only one sample and found no BRAF V600E point mutation. In summary, we found over-expression of EGFR in the majority cases of penile SCC, but only rare expression of RASSF1A, rare KRAS mutation, and no BRAF mutation in penile SCC. These data suggest that anti-EGFR agents may be potentially considered as therapeutic options in penile SCC.

Alternative HER/PTEN/Akt pathway activation in HPV positive and negative penile carcinomas

Background

The pathogenesis of penile squamous cell carcinoma (PSCC) is not well understood, though risk factors include human papillomavirus (HPV). Disruption of HER/PTEN/Akt pathway is present in many cancers; however there is little information on its function in PSCC. We investigated HER family receptors and phosphatase and tension homolog (PTEN) in HPV-positive and negative PSCC and its impact on Akt activation using immunohistochemistry and fluorescent in situ hybridisation (FISH).

Methodology/Principal Findings

148 PSCCs were microarrayed and immunostained for phosphorylated EGFR (pEGFR), HER2, HER3, HER4, phosphorylated Akt (pAkt), Akt1 and PTEN proteins. EGFR and PTEN gene status were also evaluated using FISH. HPV presence was assessed by PCR. pEGFR expression was detected significantly less frequently in HPV-positive than HPV-negative tumours (p = 0.0143). Conversely, HER3 expression was significantly more common in HPV-positive cases (p = 0.0128). HER4, pAkt, Akt and PTEN protein expression were not related to HPV. HER3 (p = 0.0054) and HER4 (p = 0.0002) receptors significantly correlated with cytoplasmic Akt1 immunostaining. All three proteins positively correlated with tumour grade (HER3, p = 0.0029; HER4, p = 0.0118; Akt1, p = 0.0001). pEGFR expression correlated with pAkt but not with tumour grade or stage. There was no EGFR gene amplification. HER2 was not detected. PTEN protein expression was reduced or absent in 62% of tumours but PTEN gene copy loss was present only in 4% of PSCCs.

Conclusions/Significance

EGFR, HER3 and HER4 but not HER2 are associated with penile carcinogenesis. HPV-negative tumours tend to express significantly more pEGFR than HPV-positive cancers and this expression correlates with pAkt protein, indicating EGFR as an upstream regulator of Akt signalling in PSCC. Conversely, HER3 expression is significantly more common in HPV-positive cases and positively correlates with cytoplasmic Akt1 expression. HER4 and PTEN protein expression are not related to HPV infection. Our results suggest that PSCC patients could benefit from therapies developed to target HER receptors.