Comprehensive Genomic Profiling of Advanced Penile Carcinoma Suggests a High Frequency of Clinically Relevant Genomic Alterations

New Therapeutic Horizons for Advanced or Metastatic Penile Cancer

Penile cancer is a rare malignancy with a poor prognosis. Studies with single-agent immune checkpoint inhibitors (ICIs) have demonstrated efficacy, but response rates are low. Studies combining ICIs with both chemotherapy and targeted therapy are ongoing. Up to 50% of penile cancer cases are associated with human papillomavirus (HPV). HPV-targeting therapies, such as HPV-targeting vaccines and T-cell receptor therapies, are an area of active investigation. Penile cancer cells also express cell surface antigens that may be targeted by the emerging class of antibody-drug conjugates.

Therapeutic Targets in Advanced Penile Cancer: From Bench to Bedside

Discovery of effective systemic therapies for patients with advanced penile cancer has been slow to occur. Comprehensive genomic profiling from several studies shed light on the molecular oncogenesis of penile squamous cell carcinoma (PSCC) and differences between HPV-related and unrelated tumors. While these two subsets of PSCC appear distinct in their biology, there are not yet specific treatment strategies recommended on that basis. Cell surface proteins have been identified that may potentially serve as drug targets for monoclonal antibodies or small molecule inhibitors. Here, we review some of the new biological insights regarding PSCC that could lead to improved therapies, as well as the related clinical trials recently completed or in progress. We conclude that antibody-drug conjugates are especially promising, as are the combinations of immune checkpoint inhibitors with other types of drugs.

Insights into the management of penile squamous cell carcinoma: from conventional approaches to emerging novel therapies

INTRODUCTION

Penile squamous cell carcinoma (PSCC), a rare genitourinary cancer, is associated with poor outcomes due to limited treatment effectiveness, especially in advanced stages.

AREAS COVERED

While chemotherapy and/or surgery remain the standard of care, emerging therapies like immunotherapy, targeted therapy, and human papillomavirus (HPV) directed therapies show promise. Key to advancing treatment is understanding the immune microenvironment to gain insights into tumor resistance mechanisms and potential therapeutic targets. The scarcity of data on PSCC is a major obstacle in advancing research for this rare cancer.

EXPERT OPINION

Future research should prioritize collaborative efforts across various research centers and countries. Enhancing data sharing and pooling resources can lead to a more comprehensive understanding of PSCC, ultimately supporting the development of precision medicine strategies tailored to this specific cancer type. This collaborative approach is essential for making significant strides in PSCC treatment and care.

Case report of penile squamous cell carcinoma continuous treatment with BRCA2 mutation

BACKGROUND

Penile squamous cell carcinoma (PSCC) is a highly aggressive malignancy with a poor prognosis. BRCA1/2 mutations are associated with impaired DNA double-strand break repair and are among the common mutations in penile cancer, potentially paving the way for poly ADP-ribose polymerase inhibitor therapy.

CASE PRESENTATION

We report a 65-year-old male with PSCC who progressed to thigh metastasis at 10 months after partial penectomy. Next-generation sequencing showed that the penis primary lesion and metastatic thigh lesion harboured a BRCA2 mutation. Chemotherapy plus immunotherapy was used for treatment, and the thigh metastasis was found to involve no tumour. Progression-free survival (PFS) lasted for 8 months until the appearance of lung metastasis. Afterwards, the patient benefited from second-line therapy of olaparib with pembrolizumab and anlotinib, and his disease was stable for 9 months. The same BRCA2 was identified in the lung biopsy. Given the tumour mutation burden (TMB, 13.97 mutation/Mb), the patient received third-line therapy with nivolumab plus ipilimumab, but PFS only lasted for 3 months, with the appearance of right frontal brain metastasis. Then, the patient was treated with radiation sequential fluzoparib therapy as fourth-line treatment, and the treatment efficacy was evaluated as PR. Currently, this patient is still alive.

CONCLUSIONS

This is the first report of penile cancer with BRCA2 mutation, receiving a combination treatment with olaparib and experiencing a benefit for 9 months. This case underscores the pivotal role of BRCA2 in influencing treatment response in PSCC, providing valuable insights into the application of targeted therapies in managing recurrent PSCC with BRCA2 alterations. This elucidation establishes a crucial foundation for further research and clinical considerations in similar cases.

Genomic Profiles and Clinical Outcomes of Penile Squamous Cell Carcinoma With Elevated Tumor Mutational Burden

Importance

Tumor mutational burden (TMB) is a putative biomarker of efficacy for immune checkpoint inhibitor (ICI) therapies of solid tumors, but not specifically for penile squamous cell carcinoma (PSCC).

Objective

To characterize biomarker features and ICI therapy outcomes associated with high TMB in PSCC in the routine clinical practice setting.

Design, Setting, and Participants

In this cohort study, 397 PSCC cases were analyzed to identify genomic alterations in more than 300 cancer-associated genes and genomic signatures, including TMB, using a hybrid capture-based comprehensive genomic profiling assay. Tumor mutational burden was categorized as low (<10 mutations per megabase [mut/Mb]), high (10-19 mut/Mb), or very high (≥20 mut/Mb). Germline status of genetic alterations was predicted using a validated somatic-germline computational method. Clinical outcomes of patients with metastatic PSCC receiving first-line ICI were abstracted using the deidentified nationwide Clinico-Genomic Database (CGDB) from January 1, 2011, through December 31, 2022.

Exposure

Comprehensive genomic profiling was performed using FoundationOne and FoundationOne CDx assays from Foundation Medicine Inc.

Main outcomes and measures

The spectrum of genetic alterations by TMB level in PSCC, the percentage of germline genetic alterations, and the outcome (overall survival with routine clinical treatment) by TMB of chemotherapy-naive patients with PSCC who received ICI treatment up front were assessed in this descriptive study.

Results

Among 397 patients (median [IQR] age, 65 [54-73] years; 266 [67.0%] of European, 83 [20.9%] of admixed American, and 34 [8.5%] of African or other genomic ancestry), the median (IQR) age (eg, 65 [53-73] years for low TMB vs 68 [61-78] years for TMB ≥10 mut/Mb) and genomic ancestry distribution (eg, European 228 of 339 [67.3%] for low TMB vs 38 of 58 [65.5%] for TMB ≥10 mut/Mb) were similar between TMB subgroups. There were 339 PSCC cases (85.4%) with low TMB, 40 cases (10.1%) with high TMB, and 18 cases (4.5%) with very high TMB. Comparisons of TMB of 10 mut/Mb or higher vs low TMB showed an enrichment of genetic alterations in PIK3CA (48.3% vs 18.3%; P < .001) and KMT2D (29.3% vs 7.7%; P < .001) and less frequent genetic alterations in CDKN2A (25.9% vs 45.7%; P = .05). Most genetic alterations did not co-occur. Human papillomavirus identification was more frequent as TMB increased: 28.3% for low TMB, 50.0% for high, and 72.2% for very high. In total, 95 of 1377 genetic alterations (6.9%) were germline. Of 10 patients identified from the CGDB receiving frontline ICIs, median (IQR) follow-up was 9.9 months. Four patients had overall survival with clinical treatment of more than 12 months, including 2 of 3 patients with TMB of 10 mut/Mb or higher.

Conclusions and Relevance

In this cohort study of advanced metastatic PSCC based on TMB levels, significant differences were observed for biomarkers in nearly 15% of patients with a TMB of 10 mut/Mb or higher. Germline testing and ICI-based therapy should be integrated into the management of selected PSCC cases.

The role of Her-2 in penile squamous cell carcinoma progression and cisplatin chemoresistance and potential for antibody-drug conjugate-based therapy

BACKGROUND

Cisplatin-based chemotherapy has been the first choice for advanced penile squamous cell carcinoma (PSCC) in the last decade, but its utility is limited by the low response rate, systemic toxicity, and chemoresistance, which contribute to a poor prognosis. There is no standard second-line therapy for advanced PSCC. Human epidermal growth factor receptor 2 (Her-2)-targeted antibody-drug conjugates (ADCs) are novel low-toxicity agents which have greatly improved clinical outcomes for several advanced cancers. We aimed to explore the expression pattern, clinical significance, and oncogenic roles of Her-2 and the therapeutic potential of Her-2-targeted ADCs in PSCC.

METHODS

Her-2 immunohistochemistry was performed for the largest single-centre PSCC cohort to date (367 patients). PSCC cell lines, cisplatin-resistant cell lines, subcutaneous xenograft, and footpad metastatic models were used to investigate the biological roles of Her-2 in PSCC progression. Cytotoxicity, apoptosis assays, and western blotting investigated the mechanism of Her-2 induced cisplatin-chemoresistance. The efficacy of Disitamab Vedotin (RC48), a Her-2-targeted ADC, was evaluated in PSCC.

RESULTS

Her-2 was identified as an adverse prognostic indicator associated with advanced Tumor-Node-Metastasis (TNM) stages and poor survival with an immunohistochemical expression rate of approximately 47.7% (1+, 23.2%; 2+, 18.0%; 3+, 6.5%) in PSCC. Her-2 promotes cell proliferation, migration, invasion, tumour progression, and cisplatin resistance in PSCC. Mechanistically, Her-2 inhibits cisplatin-induced cell apoptosis by the activation of Akt phosphorylation at Ser473 and disrupts the balance between proapoptotic and antiapoptotic proteins. Meanwhile, cisplatin-resistant PSCC cells present aggressive oncogenic abilities and Her-2 upregulation. More importantly, RC48 displayed remarkable antitumor activities in both Her2-positive and cisplatin-resistant PSCC tumours.

CONCLUSION

Our study suggests that Her-2 is an available therapeutic biomarker for PSCC. Her-2-targeted ADC might have the potential to improve clinical outcomes in high-risk Her-2-positive advanced PSCC patients and provide precious second-line clinical choice for appropriate cisplatin-based chemoresistance patients.

Different Mutational Landscapes in Human Papillomavirus-Induced and Human Papillomavirus-Independent Invasive Penile Squamous Cell Cancers

Penile squamous cell carcinomas (SCC) are rare cancers that arise after transforming human papillomavirus (HPV) infections or independent of HPV in the background of chronic dermatoses. Limited knowledge about genetic alterations driving penile carcinogenesis comes from studies of mainly small cohorts of typically mixed etiology. In this comparative genetic study of HPV-induced and HPV-independent invasive penile SCC of 156 patients from a single institution in a low-incidence country, hotspots of 50 cancer-relevant genes were analyzed with targeted next-generation sequencing. Seventy-nine of 156 SCC were classified as HPV induced, and 77 of 156 SCC arose independent of HPV. Only 28 (35%) of 79 HPV-induced penile SCC, but 69 (90%) of 77 HPV-independent SCC carried somatic gene mutations. PIK3CA, FGFR3, and FBXW7 mutations occurred in both groups in similar numbers as seen in other human cancers. In contrast, mutations in TP53 (44/77; 57%), CDKN2A (35/77; 45%), and HRAS (13/77; 17%) genes occurred with one exception of a HIV positive patient exclusively in HPV-independent SCC with a frequent co-occurrence of TP53 and CDKN2A mutations (28/77; 42%). Mutations in multiple genes occurred in 9 (11%) of 79 HPV-induced SCC versus 47 (62%) of 77 HPV-independent SCC (χ2; P < .001). More than one mutation per gene (multi hits) was characteristic for HPV-independent SCC in 14 (18%) of 77 compared with only 3 (4%) of 79 HPV-induced SCC (χ2; P < .001). The total number of mutations in HPV-induced penile SCC (47 mutations) was significantly lower than that in HPV-independent SCC (143 mutations; Welsh test; P < .001). The presence of somatic driver gene mutations did not correlate with the age of patients, histology, or tumor stage of the primary SCC in either etiologic group, suggesting that acquisition of driver gene mutations is an early event after invasion. This large cohort analysis identified characteristic differences in mutational landscapes for the 2 etiologies. While genetic mutations in tumor suppressor genes drive HPV-independent penile carcinogenesis, oncogenic action of E6 and E7 substitute for mutations in HPV-induced SCC. A subgroup of patients with advanced SCC may be candidates for targeted therapy and clinical trials, although the majority of advanced penile SCC remain a therapeutic challenge.

[Systemic treatment of penile cancer: New concepts? New achievements?]

Systemic chemotherapy has been in use for metastatic penile carcinoma for years, but its success is limited. Its significance is largely associated with its role in multimodal treatment for lymphatic metastasis in the context of radical lymph node surgery. In cases of limited lymph node involvement, the combination of surgical treatment plus cisplatin- and taxane-based triple combinations may be curative. Advances in the understanding of molecular changes in penile cancer and the search for potential therapy targets have led to numerous studies. Although there is evidence of efficacy of immunotherapeutics, no significant therapeutic improvements have been seen in the clinical routine.

Increased HRD score in cisplatin resistant penile cancer cells

BACKGROUND/INTRODUCTION

Penile cancer is a rare disease in demand for new therapeutic options. Frequently used combination chemotherapy with 5 fluorouracil (5-FU) and cisplatin (CDDP) in patients with metastatic penile cancer mostly results in the development of acquired drug resistance. Availability of cell culture models with acquired resistance against standard therapy could help to understand molecular mechanisms underlying chemotherapy resistance and to identify candidate treatments for an efficient second line therapy.

METHODS

We generated a cell line from a humanpapilloma virus (HPV) negative penile squamous cell carcinoma (UKF-PEC-1). This cell line was subject to chronic exposure to chemotherapy with CDDP and / or 5-FU to induce acquired resistance in the newly established chemo-resistant sublines (PEC-1^rCDDP²⁵⁰⁰, adapted to 2500 ng/ml CDDP; UKF-PEC-1^r5-FU⁵⁰⁰, adapted to 500 ng/ml 5- FU; UKF-PEC1^rCDDP²⁵⁰⁰/^r5-FU⁵⁰⁰, adapted to 2500 ng/ml CDDP and 500 ng/ml 5 -FU). Afterwards cell line pellets were formalin-fixed, paraffin embedded and subject to sequencing as well as testing for homologous recombination deficiency (HRD). Additionally, exemplary immunohistochemical stainings for p53 and gammaH2AX were applied for verification purposes. Finally, UKF-PEC-1^rCDDP²⁵⁰⁰, UKF-PEC-1^r5-FU⁵⁰⁰, UKF-PEC1^rCDDP²⁵⁰⁰/^r5-FU⁵⁰⁰, and UKF-PEC-3 (an alternative penis cancer cell line) were tested for sensitivity to paclitaxel, docetaxel, olaparib, and rucaparib.

RESULTS AND CONCLUSIONS

The chemo-resistant sublines differed in their mutational landscapes. UKF-PEC-1^rCDDP²⁵⁰⁰ was characterized by an increased HRD score, which is supposed to be associated with increased PARP inhibitor and immune checkpoint inhibitor sensitivity in cancer. However, UKF-PEC-1^rCDDP²⁵⁰⁰ did not display sensitivity to PARP inhibitors.

Conversion therapy for advanced penile cancer with tislelizumab combined with chemotherapy: A case report and review of literature

BACKGROUND

Locally advanced penile squamous cell carcinoma with unresectable inguinal lymph node metastasis has a poor prognosis, and surgical treatment alone offers limited benefits. Effective conversion therapy regimens are urgently needed.

CASE SUMMARY

We describe a locally advanced penile squamous cell carcinoma patient with bulky, fixed inguinal lymph node metastasis complicated with genital skin ulcers who underwent inguinal lymph node dissection and achieved a pathological complete response with conversion therapy comprising immunotherapy plus chemotherapy.

CONCLUSION

For unresectable locally advanced penile squamous cell carcinoma, neoadjuvant immunotherapy combined with chemotherapy is a potential treatment approach. Biomarkers of immunotherapy efficacy need to be explored, and clinical trials are needed to test these strategies.

miRNA and mRNA Expression Profiles Associated with Lymph Node Metastasis and Prognosis in Penile Carcinoma

Penile cancer (PeC) is a rare disease, and no prognostic biomarkers have been adopted in clinical practice yet. The objective of the present study was to identify differentially expressed miRNAs (DEmiRs) and genes (DEGs) as potential biomarkers for lymph node metastasis and other prognostic factors in PeC. Tumor samples were prospectively obtained from 24 patients with squamous cell carcinoma of the penis. miRNA microarray analysis was performed comparing tumors from patients with inguinal lymph node metastatic and localized disease, and the results were validated by qRT-PCR. Eighty-three gene expression levels were also compared between groups through qRT-PCR. Moreover, DEmiRs and DEGs expression levels were correlated with clinicopathological variables, cancer-specific (CSS), and overall survival (OS). TAC software, TM4 MeV 4.9 software, SPSS v.25.0, and R software v.4.0.2 were used for statistical analyses. We identified 21 DEmiRs in microarray analysis, and seven were selected for validation. miR-744-5p and miR-421 were overexpressed in tissue samples of metastatic patients, and high expression of miR-421 was also associated with lower OS. We found seven DEGs (CCND1, EGFR, ENTPD5, HOXA10, IGF1R, MYC, and SNAI2) related to metastatic disease. A significant association was found between increased MMP1 expression and tumor size, grade, pathological T stage, and perineural invasion. Other genes were also associated with clinicopathological variables, CSS and OS. Finally, we found changes in mRNA–miRNA regulation that contribute to understanding the mechanisms involved in tumor progression. Therefore, we identified miRNA and mRNA expression profiles as potential biomarkers associated with lymph node metastasis and prognosis in PeC, in addition to disruption in mRNA–miRNA regulation during disease progression.

RGS20 Promotes Tumor Progression through Modulating PI3K/AKT Signaling Activation in Penile Cancer

Regulator of G protein signaling 20 (RGS20) plays an important role in regulating neuronal G protein-coupled receptor signaling; however, its expression and oncogenic function in penile cancer (PC) remains unclear. Here, we observed high RGS20 expression in PC tissues compared to normal/adjacent penile tissues, which was closely associated with tumor stage, nodal status, and pelvic metastasis in our PC cohort. The cellular functional analysis of RGS20 revealed that manipulation of the RGS20 expression markedly affected cell viability, BrdU incorporation, soft agar clonogenesis, caspase-3 activity, and cell migration/invasion in PC cell models. Moreover, RGS20 could interact with PI3K p85α subunit and regulate PI3K/AKT signaling activation in PC cell lines. Knockdown of the PI3K p85α or p110α subunit attenuated cell viability, BrdU incorporation, soft agar clonogenesis, and cell migration/invasion in PC cell lines. In contrast, the overexpression of constitutively activated PI3K p110α mutant restored cell proliferation and cell migration/invasion caused by RGS20 depletion in PC cells. Consistent with the in vitro findings, RGS20 depletion attenuated PI3K/AKT signaling activation and suppressed tumor growth in a murine xenograft model. Importantly, the high RGS20 expression was associated with PI3K/AKT signaling activation and unfavorable progression-free/overall survival, highlighting the clinical relevance of RGS20/PI3K/AKT signaling in PC. In conclusion, the aberrant RGS20 expression may serve as a diagnostic and prognostic marker for PC. RGS20 may promote PC progression through modulating PI3K/AKT signaling activation, which may assist with the development of RGS20-targeting therapeutics in the future.

RAB20 Promotes Proliferation via G2/M Phase through the Chk1/cdc25c/cdc2-cyclinB1 Pathway in Penile Squamous Cell Carcinoma

RAB20, a member of the RAS GTPase oncogene family, is overexpressed in several cancers with poor outcomes, promoting tumorigenesis and inducing genomic instability. Here, we performed comprehensive genomic sequencing on eight penile squamous cell carcinoma (PSCC) and normal tissue pairs and found that RAB20 was upregulated in tumors, especially in metastatic lymph nodes. RAB20 overexpression in tumors was further verified by qPCR, Western blotting, and immunohistochemistry of our newly established PSCC cell lines and paired tissues. The clinical significance of RAB20 was validated in 259 PSCC patients, the largest cohort to date, and high RAB20 expression positively correlated with the T, N, M status, extranodal extension, and clinical stage (all p < 0.01). RAB20 was an unfavorable independent prognostic indicator in the survival analysis (p = 0.011, HR = 2.090; 95% Cl: 1.183−4.692), and PSCC patients with high RAB20 expression experienced shorter 5-year cancer-specific survival times (p < 0.001). Furthermore, tumorigenesis assays demonstrated that RAB20 knockdown inhibited cell proliferation, migration, and colony formation in vitro and tumor growth in vivo. RAB20 depletion also induced PSCC cell cycle arrest at G2/M by increasing Chk1 expression and promoting cdc25c phosphorylation to reduce cdc2-cyclinB1 complex formation. Our study revealed an oncogenic role for RAB20 in promoting PSCC cell proliferation at the G2/M phase via the Chk1/cdc25c/cdc2-cyclinB1 pathway. Thus, RAB20 could be a promising prognostic biomarker of advanced PSCC with poor patient survival outcomes and could be a potential therapeutic target.

Innovative systemic therapies for penile cancer

PURPOSE OF REVIEW

The purpose of this review is to look at recent advancements and treatment options of systemic therapies to treat penile squamous cell carcinoma (PSCC). PSCC is a rare cancer that remains with limited funding for research and systemic therapy development. This review aims to discuss the most recent advancements in systemic treatments and our understanding of PSCC.

RECENT FINDINGS

Neoadjuvant chemotherapy (NAC) and adjuvant therapy remain integral parts of treatment in locally advanced PSCC. New potential drug regimens are being studied to expand on the availability of first-line regimen options. There has been a large development in discoveries of cellular pathways and immune system targets as potential treatment options but these therapies as of today have limited trial evidence and currently have no support to be used in a clinical setting.

SUMMARY

PSCC is a rare genitourinary cancer with limited treatment options for patients with advanced disease that is refractory to chemotherapy. Although many new therapies targeting the immune system and cellular pathways are being developed for other studies, clinical and translational research for PSCC are still understudied and underfunded.

Genome-Wide Profiling Reveals HPV Integration Pattern and Activated Carcinogenic Pathways in Penile Squamous Cell Carcinoma

Simple Summary

Penile squamous cell carcinoma (PSCC) has been regarded as an HPV-related cancer for a long time. However, the integration pattern and carcinogenic pathways of HPV in PSCC remain unclear. The results of this study provide insights into the HPV-related carcinogenic mechanism in PSCC, which may be less prone to involvement in the traditional E6/E7 carcinogenic process, and are characterized by effects on the host genome, which result in the inactivation of tumor suppressors (CADM2, etc.) and the activation of oncogenes (KLF5, etc.), thus activating oncogenic signaling pathways (MAPK, JAK/STAT, etc.). This study could enhance our understanding of HPV integration and pave the way for subsequent HPV studies in PSCC.

Abstract

Human papillomavirus (HPV) is a significant etiologic driver of penile squamous cell carcinoma (PSCC). The integration pattern of HPV and its carcinogenic mechanism in PSCC remain largely unclear. We retrospectively reviewed 108 PSCC cases who received surgery between 2008 and 2017. Using high-throughput viral integration detection, we identified 35 HPV-integrated PSCCs. Unlike cervical cancer, the HPV E2 oncogene was not prone to involvement in integration. Eleven of the 35 (31.4%) HPV-integrated PSCCs harbored intact HPV E2; these tumors had lower HPV E6 and E7 expression and higher expression of p53 and pRb proteins than those with disrupted E2 did (p < 0.001 and p = 0.024). Integration breakpoints are preferentially distributed in or near host genes, including previously reported hotspots (KLF5, etc.) and newly identified hotspots (CADM2, etc.), which are mainly involved in oncogenic signaling pathways (MAPK, JAK/STAT, etc.). Regarding the phosphorylation levels of JNK, p38 was higher in HPV-positive tumors with MAPK-associated integration than those in HPV-positive tumors with other integration and those in HPV-negative tumors. In vitro, KLF5 knockdown inhibited proliferation and invasion of PSCC cells, while silencing CADM2 promoted migration and invasion. In conclusion, this study enhances our understanding of HPV-induced carcinogenesis in PSCC, which may not only rely on the E6/E7 oncogenes, but mat also affect the expression of critical genes and thus activate oncogenic pathways.

Systemic treatment of penile squamous cell carcinoma-hurdles and hopes of preclinical models and clinical regimens: a narrative review

Despite contemporary research efforts, the prognosis of penile squamous cell carcinoma (PeSCC) has not significantly improved over the past decade. Despite frequently encountered patient-related delayed medical consultations impairing outcomes, several other aspects contribute to the lack of advancement in the treatment of this condition. One essential reason is that translational research, a prerequisite for the clinically successful disease management, is still at an early stage in PeSCC as compared to many other malignancies. Preclinical experimental models are indispensable for the evaluation of tumor biology and identification of genomic alterations. However, since neither commercial PeSCC cell lines are available nor xenograft models sustainably established, such analyses are challenging in this field of research. In addition, systemic therapies are less effective and toxic without decisive breakthroughs over recent years. Current systemic management of PeSCC is based on protocols that have been investigated in small series of only up to 30 patients. Thus, there is an unmet medical need for new approaches necessitating research efforts to develop more efficacious systemic strategies. This review aims to highlight the current state of knowledge in the molecular alterations involved in the etiology and ensuing steps for cancer progression, existing preclinical models of translational research, clinically relevant systemic protocols, and ongoing clinical trials.

Correlation Between the Evolution of Somatic Alterations During Lymphatic Metastasis and Clinical Outcome in Penile Squamous Cell Carcinoma

Penile squamous cell carcinoma (PSCC) is a rare malignancy with poor survival after standard treatment. Although genomic alterations of PSCC have been characterized in several latest studies, the association between the formation of somatic landscape and regional lymph node metastasis (LNM), an important predictor for patient survival, has not been comprehensively investigated. Here, we collected formalin-fixed paraffin-embedded tumor tissue and matched normal samples of 32 PSCC patients, including 14 LNM patients and 18 clinically node-negative patients, to implement a whole-exome sequencing. Comparison of genomic features among different lymph node status subgroups was conducted after genomic profiling and its effects on patient survival were explored. Top-ranked recurrent gene mutants in our PSCC cohort were TP53 (13/32), NOTCH1 (12/32), CDKN2A (11/32), TTN (9/32) and FAT1 (8/32), mainly identified in the Notch, Hippo, cell cycle, TP53, RTK-RAS and PI3K pathways. While CDKN2A was confirmed to be the driver gene in all PSCC patients, certain gene mutants were significantly enriched in LNM involved patients, including TP53 (9/14 vs. 4/18, p = 0.029) and GBF1 (4/14 vs. 0/18, p = 0.028). Overall survival stratification of PSCC patients were found to be significantly correlated with mutations of three genes, including PIK3CA (Hazard ratio [HR] = 4.15, p = 0.029), CHD7 (HR = 4.82, p = 0.032) and LAMC3 (HR = 15.9, p < 0.001). PIK3CA and LAMC3 held a higher prevalence in patients with LNM compared to those without LNM (PIK3CA: 3/14 vs. 1/18, LAMC3: 2/14 vs. 1/18). Our finding demonstrated that genomic divergence exists across PSCC patients with different lymph node statuses, and it may be correlated with their survival outcome. It helps delineate somatic evolution during tumor progression and perfect potential therapeutic intervention in this disease.

Cemiplimab for Cisplatin Resistant Metastatic Penile Cancer

We report on a 75-year old man who presented with metastatic, squamous-cell carcinoma (SCC) of the penis whose disease had progressed after radiotherapy (RT) and cisplatin-based chemotherapy (CT). A strong PD-L1 expression as well as a CDKN2A mutation was documented, and he was given cemiplimab every 3 weeks at time of disease progression. Complete response (CR) was demonstrated after 10 cycles, and no toxicity was reported. However, this treatment was stopped after 13 cycles when the patient developed moderate severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pneumonitis which required a 2-week hospitalization for oxygen support. Six months later, he remains in CR. To our knowledge, this is the first demonstration of a CR with cemiplimab in a metastatic penile SCC patient previously treated with CT and RT for relapse. Furthermore, the patient remains disease-free despite cemiplimab was withdrawn due to SARS-CoV-2 pneumonitis.

Downregulation of miR-145 is associated with perineural invasion in penile carcinoma

Background

Human papillomavirus (HPV) infection is a risk factor for penile cancer (PC). The miR-145 expression has been correlated to this virus genomic amplification. In this context, this work aims to determine the expression level of miR-145 in penile tumors infected by high-risk HPV and correlate it with the clinicopathological characteristics of the tumor and protein expression of p53.

Methods

Formalin-fixed paraffin-embedded from 52 patients with PC, at diagnosis and prior to any cancer treatment, were obtained. HPV identification was performed by nested type PCR, and miR-145 expression was obtained by qRT-PCR. Immunohistochemical analysis of p53 and Ki-67 was performed.

Results

Tumoral miR-145 expression was significantly lower compared to adjacent tissue. Additionally, there was a significant reduction of miR-145 expression in invasion perineural, histological associated HPV, and absence of p53 expression in positive HPV cases. HPV infection was detected in 86.5%, the most frequent HPV16. Reduced disease-free survival was observed in patients with low expression of miR-145.

Conclusions

Our data suggest that the underexpression of miR-145 may be triggered by HPV action, decreasing protein expression of p53, and being correlated with perineural invasion. Therefore, the deregulation of miR-145 provides clues as to the potential role in penile carcinogenesis and is also a potential candidate for validation in noninvasive samples.

New Insights into the Molecular Profile of Penile Squamous Cell Carcinoma

Genomic alterations in penile squamous cell carcinoma (PSCC) appear similar to squamous cell carcinomas of the head and neck and esophagus but not lung, skin, bladder, and cervix. PSCCs display genomic heterogeneity, low mutation burden, and potentially actionable alterations in the Notch, DNA repair, kinase, and cell-cycle pathways.See related article by Chahoud et al., p. 2560.

Management of Advanced Penile Cancer

Penile squamous cell carcinoma (PSCC) is a rare cancer, with approximately 2000 new cases in the United States and 35,000 globally every year. Multiple risk factors are involved in PSCC, but most importantly, the high-risk human papillomavirus infection is thought to be present in approximately 50% of cases. Penile squamous cell carcinoma presents as localized or locally advanced disease. Multiple prognostic markers have been explored over the past 3 decades, but lymph node status remains the strongest predictor of clinical outcomes. Surgical decisions are based on the primary tumor pathologic findings, nodal clinical examination, and imaging results. Most patients with high-risk advanced PSCC benefit from a multimodal treatment approach combining chemotherapy with consolidation surgical treatment. The role of neoadjuvant chemotherapy with radiation therapy has not been well explored in PSCC. Prospective clinical studies, like the International Penile Advanced Cancer Trial, have been launched to provide high-level evidence for multimodal treatment. The International Penile Advanced Cancer Trial is the first randomized clinical trial among patients with PSCC and is currently accruing, with the expectation to generate results in 2023. Unfortunately, most patients with high-risk locally advanced PSCC will have relapsed or refractory cancer after cisplatin-based combination chemotherapy. These patients have dismal outcomes with salvage chemotherapy, highlighting the major unmet need to expand our knowledge of the disease's biology and develop clinical trials that use novel systemic agents. This narrative review synthesizes relevant publications retrieved from PubMed. Our aim is to discuss current approaches in the management of PSCC, summarize ongoing efforts to improve care, and identify future areas for enhancing our understanding of the disease.

Whole-exome Sequencing in Penile Squamous Cell Carcinoma Uncovers Novel Prognostic Categorization and Drug Targets Similar to Head and Neck Squamous Cell Carcinoma

PURPOSE

Penile squamous cell carcinoma (PSCC) is rare with limited treatment options. We report the first whole-exome sequencing (WES) analysis and compare the molecular landscape of PSCC with other squamous cell carcinomas (SCC), with the goal to identify common novel targets.

EXPERIMENTAL DESIGN

PSCC and matched normal penile tissues from 34 prospectively followed patients, underwent genomic WES and human papilloma virus testing. We performed tumor mutation signature estimation by two methods, first to identify APOBEC-related mutation enrichments and second to classify PSCC-enriched mutational patterns based on their association with the Catalogue of Somatic Mutations in Cancer mutation signatures. We performed an extensive genomic comparison between our PSCC cohort and other SCCs in The Cancer Genome Atlas studies.

RESULTS

We identified that most PSCC samples showed enrichment for Notch pathway (n = 24, 70.6%) alterations, comparable with head and neck squamous cell carcinoma (HNSC). PSCC mutation signatures are most comparable with HNSC signatures. PSCC samples showed an enrichment of two distinct mutational signatures, the first, associated with oncogenic activity of AID/APOBEC, and the second, associated with defective DNA mismatch repair and microsatellite instability. MP1 enrichment was positively correlated with increased tumor mutation burden (TMB; CC, 0.71; P < 0.0001) and correlated with significantly worse survival in comparison with those with the MP2 subset [HR, 10.2 (1.13-92.9); P = 0.039]. We show that a subset of PSCC (38%), with enrichment of APOBEC-related mutation signature, had significantly higher TMB and worse overall survival in comparison with non-APOBEC-enriched subset [HR, 2.41 (1.11-6.77); P = 0.042].

CONCLUSIONS

This study identified novel druggable targets and similarities in mutational signatures between PSCC and HNSC with potential clinical implications.See related commentary by McGregor and Sonpavde, p. 2375.

Molecular stratification by BCL2A1 and AIM2 provides additional prognostic value in penile squamous cell carcinoma

Background: Lymph node metastasis is the most unfavorable prognostic factor of penile squamous cell carcinoma (PSCC). However, patients with the same lymph node status have different outcomes, and molecular classifiers for precise prognostic assessments are lacking.

Methods: Comprehensive genomic profiling and high-content proliferation screening were performed in eight PSCC and normal tissue pairs and in cell lines. BCL2A1 and AIM2 were selected and further evaluated by qPCR and Western blot. The clinical relevance and prognostic value of the target genes were validated via immunohistochemistry in a cohort of 220 PSCC patients with a defined pN stage. Finally, the biological functions and molecular mechanisms of BCL2A1 and AIM2 were investigated in vitro and in vivo.

Results: BCL2A1 and AIM2 were both upregulated in PSCC tissues and associated mostly with cell proliferation. Staining for either BCL2A1 or AIM2 revealed that both are correlated with pN status, extranodal extension, clinical stage and cancer-specific survival (CSS). Compared to patients who are single-positive or double-negative for BCL2A1 and AIM2, those overexpressing both genes had a higher risk of tumor progression and the poorest survival in the pN0 (5-year CSS: 63.3% vs. 94.9% and 100.0%, respectively, p = 0.000) and pN+ subsets (5-year CSS: 24.1% vs. 45.7% and 55.1%, respectively, p = 0.035). Molecular biofunction and mechanistic studies demonstrated that BCL2A1 and AIM2 knockdown inhibited tumorigenesis via the AIM2/NF-κB/BCL2A1/MAPK/c-Myc signaling pathway.

Conclusions: BCL2A1 and AIM2 promote PSCC progression. Integrating BCL2A1 and AIM2 as novel molecular classifiers with pN stage provides additional information for the prognosis and treatment of PSCC patients.

SHCBP1 regulates STAT3/c-Myc signaling activation to promote tumor progression in penile cancer

A challenge in developing novel strategies for penile cancer (PC) is the limited understanding of the regulatory mechanisms involved in PC development. This study aims to examine the expression of SHC SH2 Domain-Binding Protein 1 (SHCBP1) in PC and to explore its oncogenic function. Aberrant SHCBP1 expression was observed in PC tissues compared with normal penile tissues. SHCBP1 expression was significantly associated with the pathological grade, T stage, nodal status, and pelvic lymph node metastasis, and could serve as an independent factor for unfavorable overall survival in PC. Manipulation of SHCBP1 expression affected cell proliferation, soft agar clonogenesis, and cell migration and invasion in PC cell lines. Moreover, we identified STAT3/c-Myc signaling as a potential downstream target of SHCBP1. SHCBP1 interacted with JAK2 and STAT3 upon EGF stimulation, which might regulate STAT3/c-Myc signaling activation in PC cells. Disruption of STAT3/c-Myc signaling attenuated cell proliferation and cell migration/invasion in PC cell lines. Nevertheless, overexpression of constitutively activated STAT3 or c-Myc rescued cell proliferation and cell migration/invasion caused by SHCBP1 depletion in PC cell lines. Consistently, SHCBP1 depletion attenuated STAT3/c-Myc signaling and suppressed tumor growth in a murine xenograft model. Importantly, correlated expression of SHCBP1, p-STAT3, and c-Myc was observed in PC tissues, confirming the clinical relevance of SHCBP1/STAT3/c-Myc signaling in PC. In conclusion, aberrant SHCBP1 expression could serve as a potential prognostic biomarker for PC. SHCBP1 might activate the STAT3/c-Myc signaling pathway to promote tumor progression in PC, which may serve as a potential target for PC treatment.

Second line salvage systemic therapy for advanced penile cancer

Most patients with advanced penile cancer will have relapsed disease after cisplatin-based combination chemotherapy. Unfortunately, these patients have dismal outcomes with salvage chemotherapy, surgery, or radiation. In this review we will discuss the available chemotherapy and targeted therapies for salvage second line systemic treatment for patients with penile cancer. We will also summarize the ongoing interventional clinical trials using immune and human papilloma virus-based therapies.

Current management and future perspectives of penile cancer: An updated review

Penile cancer (PeCa) is a rare disease worldwide, accounting for less than one percent of all malignancies in men. It usually presents as a painless ulcer or lump on the head of the penis. Squamous cell carcinoma represents the most common histological subtype of PeCa, with pathogenesis intimately linked to chronic Human Papilloma Virus (HPV) infection. Surgery is the cornerstone for the treatment of primary PeCa with potential mutilating outcome depending on the nodal extension of the disease. However, in case of extensive lymph node involvement, multidisciplinary treatment including perioperative chemotherapy and inclusion in clinical trial should be considered. To date, advanced or metastatic disease still have poor prognosis and are a therapeutic challenge with limited options, highlighting the need of new treatments and further investigations. Growing efforts to identify molecular alterations, understand the role of HPV and characterize immune contexture have expanded over the past years, providing further perspectives in prognostication, predictive biomarkers and therapeutic intervention. In this review, we provide an updated overview of current management of PeCa focusing on perioperative strategy. We discuss about new insights of the biology of PeCa and comment future directions in the field.

Future directions in advanced penile cancer - mechanisms of carcinogenesis and a search for targeted therapy

Penile squamous cell carcinoma (SCC) is a rare and aggressive urological malignancy. Advanced penile SCC requires multimodal management, including surgery and systemic therapy. Given its rarity, there have been few substantial advances in our understanding of the molecular and genomic drivers of penile SCC, especially for patients with relapsed or advanced disease. In this review, we discuss the molecular and genomic landscape of penile SCC, clinical trials in progress and implications for novel therapeutic targets. Future work should focus on preclinical models to provide a platform for investigation and validation of new molecular pathways for testing of therapeutics.

Metastatic penile squamous cell carcinoma with dramatic response to combined checkpoint blockade with ipilimumab and nivolumab

INTRODUCTION

Prognosis for patients with lymph node positive or metastatic penile squamous cell carcinoma remains poor. Chemotherapy with paclitaxel, ifosfamide, and cisplatin (TIP regimen) is recommended as a first-line option in this cohort of patients. No standard preferred subsequent-line therapy exists for patients with relapsed or refractory penile carcinoma following TIP chemotherapy. Molecular pathogenesis of penile cancer can be subdivided into human papilloma virus-dependent and human papilloma virus-independent pathways. Recent studies have demonstrated increased expression of programmed death ligand-1 in some penile tumors, commonly those that are human papilloma virus-negative. Given the rarity of penile carcinoma in industrialized countries and lack of effective therapies, checkpoint inhibitors may be an attractive treatment option for this subset of patients.

CASE REPORT

We report a case of metastatic penile cancer refractory to TIP chemotherapy, with a dramatic treatment response to ipilimumab and nivolumab. Molecular profiling of this tumor showed a high programmed death ligand-1 expression, high tumor mutational burden, high microsatellite instability, and alterations in DNA mismatch repair genes.

DISCUSSION

This case highlights another dimension of information that may be gained with molecular genomic profiling of penile tumors, providing insight into the biologic behavior of this neoplasm and assessing for predictive biomarkers of response to immune checkpoint inhibitors.

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.

Genetics and penile cancer: recent developments and implications

PURPOSE OF REVIEW

We summarize the recent developments in the molecular landscape of penile squamous cell carcinoma (PSCC).

RECENT FINDINGS

Recent genomic studies have demonstrated a molecular convergence of PSCC with other squamous cell carcinomas (SCCs) from different organ sites. Similarly, human papillomavirus (HPV)-related PSCCs appear to have epigenetic and genomic similarities with other HPV-related cancers. This could have implications on future HPV-related cancer trial design. Growing efforts to characterize recurrent gene alterations in PSCC have expanded our understanding over the past years, showing a predominance of tumor suppressor gene alterations such as TP53 and NOTCH1. In addition, these studies have demonstrated that at least 30% of PSCC cases have targetable gene alterations. Further, the similar tumor mutational burden with other SCCs and the relatively high rates of programmed death-1 (PD-1) positive expression in PSCC constitute the rationale for investigation of PD-1 inhibition in ongoing clinical trials. Multiple studies have identified potential epigenetic and RNA signatures predictive of metastasis or survival, but these still require validation in larger cohorts.

SUMMARY

PSCC appears to be genomicaly similar to other SCCs and HPV-related cancers. This provides the rationale and opportunity to include a rare tumor like PSCC in future 'basket type' trials using novel agents targeting multiple SCCs that may exhibit similar biology.

MIR-107, MIR-223-3P and MIR-21-5P Reveals Potential Biomarkers in Penile Cancer

BACKGROUND

Inguinal lymph node involvement is the main prognostic factor in patients with penile cancer. However, there is a lack of marker/s for lymph node metastasis. microRNAs have been investigated as potential markers for prognosis of various types of cancer. Taking this into consideration, our main goal was to determine the association of miR-223-3p, miR-107, and miR-21-5p expression with clinicopathological characteristics, as well as presence of lymph node metastasis in patients with penile cancer.

METHODS

Formalin-fixed paraffin-embedded penile squamous cell carcinoma specimens from 50 patients, at diagnosis and prior to any cancer treatment, were obtained. Tissue samples comprising at least 70% malignant cells and adjacent non-tumor tissues were evaluated by using qRT-PCR for expression level of miR-223-3p, miR-107 and miR-21-5p. Additionally, molecular identification of HPV was performed by PCR, and the expression levels of PTEN were analyzed by immunohistochemistry.

RESULTS

Penile squamous cell carcinoma primary tumors presented higher expression of miR-223-3p, miR-107, and miR-21-5p when compared to non-tumor adjacent tissues. Upregulation of miR-223-3p was associated lymph node metastasis. Higher expression of miR-107 was associated with worsening of prognosis (as observed by histological grade II and III, tumors bigger than 2.0 cm, stage III and IV, and lower disease-free survival). In addition, higher expression of miR-107 and miR-21-5p was correlated to the absence of PTEN protein expression.

CONCLUSIONS

Our data demonstrate that higher expression of miR-223-3p, miR-107, and miR-21-5p is correlated with poor prognosis in penile cancer. The upregulation of these microRNAs potentially affect critical cancer pathways and may be important for the prognosis and response to therapy in penile cancer.

Mutational landscape of penile squamous cell carcinoma in a Chinese population

Penile squamous cell carcinoma (PSCC) is a malignancy that affects the skin and tissues of the penis, but the knowledge of pathogenesis and carcinogenesis is limited. Here, we characterize the PSCC genomic landscape using whole-exome sequencing. Of the 30 paired blood and tumor samples, we identified recurrent mutations in 11 genes; confirmed previous findings for FAT1 (4/30), HRAS (4/30), NOTCH1 (4/30), TP53 (3/30) and PIK3CA (3/30); and revealed novel candidate driver genes [CASP8 (4/30), SLITRK2 (3/30), FLG (3/30) and TRRAP (3/30)]. Our in vitro experiments suggested CASP8 was involved in mediating TRAIL-induced apoptosis of penile cancer cell lines. We also observed the frequently altered pathways for potential therapeutic implications: alterations in the Notch (30% of sample altered), RTK-RAS (26.7% altered) and Hippo (23.3% altered) pathways accounted for over 50% of tumors. The frequently altered genes (>10%) in these pathways were proved to be expressed in penile tumors by immunohistochemistry assay. These findings provide new insight into the mutational and pathway landscapes of PSCC and suggest potential novel therapeutic opportunities for this malignancy.

P53 Codon 72 Polymorphism and Risk for Squamous Cell Carcinoma of the Penis: A Caucasian Case-Control Study

Squamous cell carcinoma of the penis is a rare but often aggressive disease. A large proportion of penile cancers are associated with HPV infection, mainly with HPV high-risk subtypes 16 and 18. From other HPV-related malignancies a link between a functional SNP in the p53 gene (rs1042522, p.Arg72Pro) and a higher disease risk in the presence of HPV is documented. The p53 p.Arg72 variant was described as a risk factor for developing a malignancy in combination with the presence of HPV as the p.72Arg variant is more prone to HPV E6 protein-mediated degradation than the p.72Pro variant. For penile carcinoma there are only sparse data available on this topic. We therefore analyzed the distribution of this p53 codon 72 SNP in a cohort of 107 penile cancer patients and a healthy control group (n=194) using Restriction Fragment Length Polymorphism (RFLP) analysis. After DNA isolation a PCR amplicon including the variant nucleotide was generated. Based on the variant nucleotide this amplicon can be cleaved into two parts or remain unaffected by a restriction enzyme. Subsequent electrophoresis allowed the discrimination of SNP alleles in the investigated sample. Comparison of the allelic variants revealed no significant differences in the distribution of this SNP between cases and controls (p=0,622). There was also no difference in SNP distribution between cases with/without HPV infection (p=0,558) or histologic variants (p=0.339). In order to strengthen the impact of our data we performed a combined analysis of all published data on this topic with our results. This ended up in SNP distribution data from 177 cases and 1149 controls. Overall, there were also no significant differences in the allelic distribution of the p53 codon 72 SNP between either cases and controls (p=0,914) or HPV-positive and HPV-negative cases (p=0,486). From this most comprehensive data available to date we conclude that there is no influence of the p53 codon 72 SNP on the risk of development of penile carcinoma in Caucasians even in the presence of HPV.

SOX2 Gene Amplification and Overexpression is Linked to HPV-positive Vulvar Carcinomas

SOX2 (SRY-related HMG-box 2) belongs to the SOX gene family of high-mobility transcription factors indispensably involved in gene regulation in pluripotent stem cells and neural differentiation. SOX2 copy number increases have been frequently reported in various types of squamous cell cancer. To better understand the effect of SOX2 aberrations on vulvar cancer phenotype and patient prognosis, we analyzed SOX2 copy number changes using fluorescence in situ hybridization and SOX2 expression by immunohistochemistry in 55 squamous cell carcinomas of the vulva. SOX2 amplification was found in 20.8% of tumors; 27.3% of vulvar carcinomas showed SOX2 protein overexpression. SOX2 amplification was correlated with SOX2 overexpression in our data set (P<0.01). Amplification of the SOX2 locus was associated with high tumor grade (P<0.05) and human papillomavirus (HPV) positivity (P<0.01). SOX2-amplified tumors showed more frequently a basaloid phenotype than nonamplified carcinomas. SOX2 protein overexpression was also correlated with basaloid phenotype and positive HPV status of vulvar carcinomas (P<0.05, each). SOX2 amplification and expression were not associated with patient overall survival. In conclusion, SOX2 copy number increases are detectable in a substantial proportion of high-grade HPV-positive vulvar carcinomas with basaloid differentiation. Our study provides further evidence for different molecular alterations in HPV-positive and HPV-negative vulvar carcinomas.

Nuclear loss and cytoplasmic expression of androgen receptor in penile carcinomas: role as a driver event and as a prognosis factor

Androgen receptor (AR) is a member of the steroid and nuclear family receptor that acts as transcription factor. AR signaling plays pivotal role in the development and progression of prostate cancer. However, the role of AR in penile cancer (PeCa) is poorly explored. Our previous molecular studies unveiled frequent AR mRNA loss in PeCa, which was further predicted as a major driver alteration in this neoplasm. Herein, we assessed the AR protein expression in 59 usual PeCa tissues and 42 surrounding normal tissues (SNT) by immunohistochemistry using a tissue microarray. In a paired analysis, we found a total absence of nuclear AR expression in PeCa while 95.2% of SNT samples presented strong nuclear AR expression (P < 0.001). Interestingly, 17 of 42 PeCa presented weak or moderate cytoplasmic AR staining, contrasting with 5 of 42 SNT (P = 0.008). Increased levels of AR cytoplasmic expression were related with poor prognosis features including advanced clinical staging (P = 0.044), compromised surgical margins (P = 0.005), and pathological inguinal node status (P = 0.047). Furthermore, AR cytoplasmic expression was also related with shorter overall survival (P = 0.032). In conclusion, the frequent loss of nuclear AR protein levels suggests a potential function in PeCa development. Based on this result, the androgen deprivation therapy is not indicated for PeCa patients. In addition, the AR cytoplasmic expression found in a significant number of cases (40.5%) showed prognostic value and pathways activated by the non-genomic AR signaling may represent a promising therapeutic strategy.

PIK3CA copy number aberration and activation of the PI3K-AKT-mTOR pathway in varied disease states of penile cancer

BACKGROUND

Therapeutic targeting of the PI3K-AKT-mTOR pathway may benefit patients with advanced penile squamous cell carcinoma (PSCC).

OBJECTIVES

To determine the prevalence of PIK3CA copy number gain and correlate this with the activity status of PI3K-AKT-mTOR pathway in pre-malignant penile intraepithelial neoplasia (PeIN) and invasive PSCC.

MATERIALS AND METHODS

Archival tissue blocks were obtained from 58 PeIN and 244 primary PSCC patients treated at St George's Hospital. PIK3CA copy number status (CNS) was assessed by fluorescence in-situ hybridisation. High-risk HPV DNA was detected with INNO-LiPA assay. p16INK4A, p-AKT and p-mTOR protein expression were assessed using immunohistochemistry (IHC).

RESULTS

Increased prevalence of PIK3CA copy number gain was seen in PSCC in comparison to PeIN (84/199 (42%) vs. 10/58 (17%); p = 0.0009). Analysis of the p-AKT and p-mTOR revealed a tendency to a more common expression of cytoplasmic p-AKT (p = 0.1318), nuclear p-AKT (p<0.0001) and cytoplasmic mTOR (p = 0.0006) in PeIN than PSCC. A significant association between p-AKT cytoplasmic immunoexpression and PIK3CA CNS (p = 0.0404) was found in PeIN.

CONCLUSION

Overall, PIK3CA copy number gain correlated with activation of the PI3K-AKT-mTOR pathway in PeIN and activation of this pathway is primarily involved in early penile carcinogenesis. Based on these results therapeutic targeting of this pathway in advanced PSCC is unlikely to produce significant clinical benefit. Future studies will need to focus on alternative therapeutic targets.

Molecular characterization and integrative genomic analysis of a panel of newly established penile cancer cell lines

Cell line models are essential tools to study the molecular mechanisms underlying tumor initiation and progression. There are limited treatment options for penile squamous cell carcinoma (PSCC), accounting for 1–2% of male tumors in developing countries, and limited progress in preclinical research in PSCC due to lacking available models with identified genomic characteristics. Here, biological and molecular characteristics and whole-genomic alterations were analyzed in a panel of PSCC cell lines newly established in our laboratory. These cell lines were all human papillomavirus (HPV)-negative, epithelial-like, immortalized, and tumorigenic in nude mice, whereas they displayed different proliferation, migration and invasion capacities in vitro, and tumorigenic ability in nude mice. They were all cisplatin sensitive, anti-EGFR therapy resistant, and androgen irresponsive. Whole-genomic sequecing analysis revealed that transition mutations (C:G>T:A and T:A>C:G) were the most common substitution types in these cell lines, whereas ERCC5, TP53, PTH1, CLTCL1, NOTCH2, MAP2K3, CDK11A/B, USP6, ADCH5, BCLAF1, CDKN2A, FANCD2, HRAS, and NOTCH1 were the most frequently altered genes. Amplifications of MYC, PLAG1, NCOA2, RUNX1T1, COX6C, and EGFR and losses of FBXW7, TET2, XPC, and FANCE were frequently observed in cell lines. The exomic variations between cell lines and their corresponding cancer tissues were highly consistent. Genetic variations were mainly involved in the MAPK, Jak-STAT, TGF-beta, Notch, and apoptosis signaling pathways. Conclusively, these panel of PSCC cell lines established in our laboratory harbor some common or specific biological characteristics and genomic variations, and they may serve as optimal models to investigate the molecular mechanisms underlying the progression, metastasis, relapses, and treatment resistance of PSCC and to develop effective treatment strategy.

Current Management Strategy for Penile Cancer and Future Directions

PURPOSE OF REVIEW

The aim of this review is to evaluate the trends in multidisciplinary management of localized penile cancer and systemic therapy for advanced disease in the evolving era of targeted and immune checkpoint therapy.

RECENT FINDINGS

Organ preservation (surgical or incorporating radiation) and reconstructive techniques are important considerations for quality of life in penile cancer survivors. Although local recurrence may be higher with organ preservation, salvage therapy appears successful. Inguinal and pelvic node management requires multidisciplinary care, including chemotherapy; optimal use of radiation has not been fully defined. Advanced in understanding the biology of penile cancer, particularly with regard to epidermal growth factor receptor (EGFR) and HPV status, have led to clinical trials of targeted and immune therapy for patients with refractory disease. Refinements in the management of penile cancer are occurring, though level 1 evidence remains scarce. Referral to specialized centers will facilitate successful completion of clinical trials to advance standard care in this disease.

Kinase analysis of penile squamous cell carcinoma on multiple platforms to identify potential therapeutic targets

Penile squamous cell carcinoma (PSCC) is an orphan malignancy with poorly understood biology and suboptimal systemic therapy. Given that kinases may be drivers and readily actionable, we performed comprehensive multiplatform analysis of kinases in PSCC tumor and normal tissue. Fresh frozen tumors were collected from 11 patients with PSCC. After macrodissection to demarcate tumor from normal tissue, the samples underwent multiplatform analysis of kinases. Next Generation Sequencing (NGS) of 517 kinase genes was performed using Agilent Kinome capture and run on the Illumina MiSeq at PE150bp. The NanoString nCounter® platform analyzed the expression of 519 kinase genes. Kinase activity of tissue lysates was measured using PamStation®12 high-content phospho-peptide substrate microarray system. Network mapping was done with GeneGo MetaCore™ and upstream kinase prediction was performed with BioNavigator and the Kinexus database. Ingenuity pathway analysis was performed to integrate elevated kinase activity and gene over-expression with coexisting missense mutations at DNA level. Top pathways upregulated in both the kinase activity and gene expression platforms were PTEN, STAT3, GNRH, IL-8 and B cell receptor signaling. Potentially relevant missense mutations were seen in 176 kinase genes, with the top altered pathways overlapping with gene overexpression being GNRH, NF-kB and STAT3 signaling. ERBB2, ERBB3 and SYK were altered on NGS and also exhibited elevated kinase activity. To summarize, multiplatform comprehensive analysis of kinases discovered potential drivers of PSCC and actionable therapeutic targets. Translational studies are necessary to validate the functional relevance of our data to make advances in this rare malignancy.