Effective combinatorial immunotherapy for penile squamous cell carcinoma

Moura A, Filho ODMM, Pessoa C, Miranda Furtado CL. Hypomethylation at H19DMR in penile squamous cell carcinoma is not related to HPV infection

Penile squamous cell carcinoma (SCC) is a rare and aggressive tumour mainly related to lifestyle behaviour and human papillomavirus (HPV) infection. Environmentally induced loss of imprinting (LOI) at the H19 differentially methylated region (H19DMR) is associated with many cancers in the early events of tumorigenesis and may be involved in the pathogenesis of penile SCC. We sought to evaluate the DNA methylation pattern at H19DMR and its association with HPV infection in men with penile SCC by bisulfite sequencing (bis-seq). We observed an average methylation of 32.2% ± 11.6% at the H19DMR of penile SCC and did not observe an association between the p16INK4a+ (p = 0.59) and high-risk HPV+ (p = 0.338) markers with methylation level. The average methylation did not change according to HPV positive for p16INK4a+ or hrHPV+ (35.4% ± 10%) and negative for both markers (32.4% ± 10.1%) groups. As the region analysed has a binding site for the CTCF protein, the hypomethylation at the surrounding CpG sites might alter its insulator function. In addition, there was a positive correlation between intense polymorphonuclear cell infiltration and hypomethylation at H19DMR (p = 0.035). Here, we report that hypomethylation at H19DMR in penile SCC might contribute to tumour progression and aggressiveness regardless of HPV infection.

Role played by MDSC in colitis-associated colorectal cancer and potential therapeutic strategies

Colitis-associated colorectal cancer has been a hot topic in public health issues worldwide. Numerous studies have demonstrated the significance of myeloid-derived suppressor cells (MDSCs) in the progression of this ailment, but the specific mechanism of their role in the transformation of inflammation to cancer is unclear, and potential therapies targeting MDSC are also unclear. This paper outlines the possible involvement of MDSC to the development of colitis-associated colorectal cancer. It also explores the immune and other relevant roles played by MDSC, and collates relevant targeted therapies against MDSC. In addition, current targeted therapies for colorectal cancer are analyzed and summarized.

Single-cell Atlas of Penile Cancer Reveals TP53 Mutations as a Driver of an Aggressive Phenotype, Irrespective of Human Papillomavirus Status, and Provides Clues for Treatment Personalization

BACKGROUND AND OBJECTIVE

TP53 loss-of-function (TP53LOF) mutations might be a driver of poor prognosis and chemoresistance in both human papillomavirus (HPV)-independent (HPV-) and HPV-associated (HPV+) penile squamous cell carcinoma (PSCC). Here, we aim to describe transcriptomic differences in the PSCC microenvironment stratified by TP53LOF and HPV status.

METHODS

We used single-cell RNA sequencing (scRNA-seq) and T-cell receptor sequencing to obtain a comprehensive atlas of the cellular architecture of PSCC. TP53LOF and HPV status were determined by targeted next-generation sequencing and sequencing HPV-DNA reads. Six HPV+ TP53 wild type (WT), six HPV- TP53WT, and four TP53LOF PSCC samples and six controls were included. Immunohistochemistry and hematoxylin-eosin confirmed the morphological context of the observed signatures. Prognostic differences between patient groups were validated in 541 PSCC patients using Kaplan-Meier survival estimates.

KEY FINDINGS AND LIMITATIONS

Patients with aberrant p53 staining fare much worse than patients with either HPV- or HPV+ tumors and WT p53 expression. Using scRNA-seq, we revealed 65 cell subtypes within 83 682 cells. TP53LOF tumors exhibit a partial epithelial-to-mesenchymal transition, immune-excluded, angiogenic, and morphologically invasive environment, underlying their aggressive phenotype. HPV- TP53WT tumors show stemness and immune exhaustion. HPV+ TP53WT tumors mirror normal epithelial maturation with upregulation of antibody-drug-conjugate targets and activation of innate immunity. Inherent to the scRNA-seq analysis, low sample size is a limitation and validation of signatures in large PSCC cohorts is needed.

CONCLUSIONS AND CLINICAL IMPLICATIONS

This first scRNA-seq atlas offers unprecedented in-depth insights into PSCC biology underlying prognostic differences based on TP53 and HPV status. Our findings provide clues for testing novel biomarker-driven therapies in PSCC.

PATIENT SUMMARY

Here, we analyzed tissues of penile cancer at the level of individual cells, which helps us understand why patients who harbor a deactivating mutation in the TP53 gene do much worse than patients lacking such a mutation. Such an analysis may help us tailor future therapies based on TP53 gene mutations and human papillomavirus status of these tumors.

Transcriptomic, Proteomic, and Genomic Mutational Fraction Differences Based on HPV Status Observed in Patient-Derived Xenograft Models of Penile Squamous Cell Carcinoma

Metastatic penile squamous cell carcinoma (PSCC) has only a 50% response rate to first-line combination chemotherapies and there are currently no targeted-therapy approaches. Therefore, we have an urgent need in advanced-PSCC treatment to find novel therapies. Approximately half of all PSCC cases are positive for high-risk human papillomavirus (HR-HPV). Our objective was to generate HPV-positive (HPV+) and HPV-negative (HPV-) patient-derived xenograft (PDX) models and to determine the biological differences between HPV+ and HPV- disease. We generated four HPV+ and three HPV- PSCC PDX animal models by directly implanting resected patient tumor tissue into immunocompromised mice. PDX tumor tissue was found to be similar to patient tumor tissue (donor tissue) by histology and short tandem repeat fingerprinting. DNA mutations were mostly preserved in PDX tissues and similar APOBEC (apolipoprotein B mRNA editing catalytic polypeptide) mutational fractions in donor tissue and PDX tissues were noted. A higher APOBEC mutational fraction was found in HPV+ versus HPV- PDX tissues (p = 0.044), and significant transcriptomic and proteomic expression differences based on HPV status included p16 (CDKN2A), RRM2, and CDC25C. These models will allow for the direct testing of targeted therapies in PSCC and determine their response in correlation to HPV status.

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.

Characterization of T cell receptor repertoire in penile cancer

Tumor-infiltrating lymphocytes (TILs) play a key role in regulating the host immune response and shaping tumor microenvironment. It has been previously shown that T cell infiltration in penile tumors was associated with clinical outcomes. However, few studies have reported the T cell receptor (TCR) repertoire in patients with penile cancer. In the present study, we evaluated the TCR repertoires in tumor and adjacent normal tissues from 22 patients with penile squamous cell carcinoma (PSCC). Analysis of the T cell receptor beta-variable (TRBV) and joining (TRBJ) genes usage and analysis of complementarity determining region 3 (CDR3) length distribution did not show significant differences between tumor and matched normal tissues. Moreover, analysis of the median Jaccard index indicated a limited overlap of TCR repertoire between these groups. Compared with normal tissues, a significantly lower diversity and higher clonality of TCR repertoire was observed in tumor samples, which was associated with clinical characteristics. Further analysis of transcriptional profiles demonstrated that tumor samples with high clonality showed increased expression of genes associated with CD8 + T cells. In addition, we analyzed the TCR repertoire of CD4 + T cells and CD8 + T cells isolated from tumor tissues. We identified that expanded clonotypes were predominantly in the CD8 + T cell compartment, which presented with an exhausted phenotype. Overall, we comprehensively compared TCR repertoire between penile tumor and normal tissues and demonstrated the presence of distinct T cell immune microenvironments in patients with PSCC.

Machine learning-based overall and cancer-specific survival prediction of M0 penile squamous cell carcinoma：A population-based retrospective study

Background

Penile cancer is a rare tumor and few studies have focused on the prognosis of M0 penile squamous cell carcinoma (PSCC). This retrospective study aimed to identify independent prognostic factors and construct predictive models for the overall survival (OS) and cancer-specific survival (CSS) of patients with M0 PSCC.

Methods

Data was extracted from the Surveillance, Epidemiology, and End Results database for patients diagnosed with malignant penile cancer. Eligible patients with M0 PSCC were selected according to predetermined inclusion and exclusion criteria. These patients were then divided into a training set, a validation set, and a test set. Univariate and multivariate COX regression analyses were initially performed to identify independent prognostic factors for OS and CSS in M0 PSCC patients. Subsequently, traditional and machine learning prognostic models, including random survival forest (RSF), COX, gradient boosting, and component-wise gradient boosting modelling, were constructed using the scikit-survival framework. The performance of each model was assessed by calculating time-dependent area under curve (AUC), C-index, and integrated Brier score (IBS), ultimately identifying the model with the highest performance. Finally, the Shapley additive explanation (SHAP) value, feature importance, and cumulative rates analyses were used to further estimate the selected model.

Results

A total of 2, 446 patients were included in our study. Cox regression analyses demonstrated that age, N stage, and tumor size were predictors of OS, while the N stage, tumor size, surgery, and residential area were predictors of CSS. The RSF and COX models had a higher time-independent AUC and C-index, and lower IBS value than other models in OS and CSS prediction. Feature importance analysis revealed the N stage as a common significant feature for predicting M0 PSCC patients' survival. The SHAP and cumulative rate analyses demonstrated that the selected models can effectively evaluate the prognosis of M0 PSCC patients.

Conclusion

In M0 PSCC patients, age, N stage, and tumor size were predictors of OS. In addition, the N stage, tumor size, surgery, and residential area were predictors of CSS. The machine learning-based RSF and COX models effectively predicted the prognosis of M0 PSCC patients.

SPP1 is associated with adverse prognosis and predicts immunotherapy efficacy in penile cancer

BACKGROUND

The effect of SPP1 in squamous cell carcinoma of the penis (PSCC) remained unknown. We attempted to clarify the function of the SPP1 gene in PSCC.

METHOD

Eight paired penile cancer specimens (including penile cancer tissue, paracancerous tissue, and positive lymph node tissue) subjected to whole transcriptome sequencing were analysed to identify differentially expressed genes. We used immunohistochemistry to detect the expression of SPP1 protein and immune cell related proteins in penile cancer tissue. Then, we performed weighted gene coexpression network analysis (WGCNA) to identify the genes related to SPP1 in penile cancer tissue and positive lymph node tissue. Based on the GSE57955 dataset, the CIBERSORT and ssGSEA algorithms were carried out to investigate the immune environment of PSCC. GSVA analysis was conducted to identify the signaling pathways related to SPP1 subgroups. Enzyme-linked immunosorbent assay (ELISA) method was adopted to detect SPP1 level in the serum of 60 patients with penile cancer.

RESULTS

Differential analysis indicated that SPP1 was the most differentially upregulated gene in both penile cancer tissues and positive lymph node tissues. Survival analysis suggested that the prognosis of the low-SPP1 group was significantly poorer than that of the high-SPP1 group. Subsequently, immune-related bioinformatics showed that SPP1 was significantly associated with B cells, CD8 + T cells, CD4 + T cells, macrophages, helper T cells, neutrophils and dendritic cells. The immunohistochemical results showed that the high-SPP1 group was characterized by relatively high expression of CD16 and relatively low expression of CD4. GSVA analysis indicated that high-SPP1 group was significantly associated with immune-related pathways such as PD-L1 expression and the PD-1 checkpoint pathway in cancer and the TNF signaling pathway. ELISA demonstrated that the serum level of SPP1 in patients with positive lymph node metastasis of penile cancer was significantly higher than that in patients with negative lymph node metastasis of penile cancer.

CONCLUSION

Our study shows that the SPP1 gene might be an effective biomarker for predicting the prognosis and the efficacy of immunotherapy in PSCC patients.

Neutrophils resist ferroptosis and promote breast cancer metastasis through aconitate decarboxylase 1

Metastasis causes breast cancer-related mortality. Tumor-infiltrating neutrophils (TINs) inflict immunosuppression and promote metastasis. Therapeutic debilitation of TINs may enhance immunotherapy, yet it remains a challenge to identify therapeutic targets highly expressed and functionally essential in TINs but under-expressed in extra-tumoral neutrophils. Here, using single-cell RNA sequencing to compare TINs and circulating neutrophils in murine mammary tumor models, we identified aconitate decarboxylase 1 (Acod1) as the most upregulated metabolic enzyme in mouse TINs and validated high Acod1 expression in human TINs. Activated through the GM-CSF-JAK/STAT5-C/EBPβ pathway, Acod1 produces itaconate, which mediates Nrf2-dependent defense against ferroptosis and upholds the persistence of TINs. Acod1 ablation abates TIN infiltration, constrains metastasis (but not primary tumors), bolsters antitumor T cell immunity, and boosts the efficacy of immune checkpoint blockade. Our findings reveal how TINs escape from ferroptosis through the Acod1-dependent immunometabolism switch and establish Acod1 as a target to offset immunosuppression and improve immunotherapy against metastasis.

Targeting the chromatin effector Pygo2 promotes cytotoxic T cell responses and overcomes immunotherapy resistance in prostate cancer

The noninflamed microenvironment in prostate cancer represents a barrier to immunotherapy. Genetic alterations underlying cancer cell-intrinsic oncogenic signaling are increasingly appreciated for their role in shaping the immune landscape. Recently, we identified Pygopus 2 (PYGO2) as the driver oncogene for the amplicon at 1q21.3 in prostate cancer. Here, using transgenic mouse models of metastatic prostate adenocarcinoma, we found that Pygo2 deletion decelerated tumor progression, diminished metastases, and extended survival. Pygo2 loss augmented the activation and infiltration of cytotoxic T lymphocytes (CTLs) and sensitized tumor cells to T cell killing. Mechanistically, Pygo2 orchestrated a p53/Sp1/Kit/Ido1 signaling network to foster a microenvironment hostile to CTLs. Genetic or pharmacological inhibition of Pygo2 enhanced the antitumor efficacy of immunotherapies using immune checkpoint blockade (ICB), adoptive cell transfer, or agents inhibiting myeloid-derived suppressor cells. In human prostate cancer samples, Pygo2 expression was inversely correlated with the infiltration of CD8+ T cells. Analysis of the ICB clinical data showed association between high PYGO2 level and worse outcome. Together, our results highlight a potential path to improve immunotherapy using Pygo2-targeted therapy for advanced prostate cancer.

Global research trends in penile cancer: Bibliometric and visualized analysis

Background

Penile cancer is a malignant tumor of the genitourinary system that mostly occurs in middle-aged and elderly men aged 50-70 years, which can seriously affect physical, psychological, and sexual health. Hundreds of original articles and reviews on penile cancer are published each year. However, a bibliometric analysis of these publications has not been performed.

Objective

This study aimed to systematically analyze and visualize penile cancer-related publications through bibliometrics and reveal identified topics, hotspots, and knowledge gaps in related fields.

Methods

Based on the Web of Science core collection database, we first analyzed the quantity and quality of publications in the field of penile cancer. Second, we profiled the publishing groups in terms of country, institution, author's publication, and cooperation network. Then, we systematized and summarized the hot topics of research.

Results

This bibliometric analysis was conducted from 2001 to 2022. The analysis identified 1,687 articles and reviews, which were published in 432 journals. The number of publications and citations on penile cancer-related research has steadily increased over the last two decades. Furthermore, academic institutions in Europe and the United States play a leading role in penile cancer research. The country, institution, journal, and author with the most publications were the United States (507), H Lee Moffitt Cancer Research Center (96), Journal of Urology (83), and Spiess P (87), respectively. The most frequently used keywords were penile cancer (743), squamous-cell carcinoma (717), cancer (380), carcinoma (232), lymphadenectomy (229). 16 keyword clustering information was obtained, including #0 male circumcision, #1 lichen sclerosus, #2 chemotherapy, #3 penile neoplasms, #4 targeted therapy, #5 resection margin, #6 cervical cancer, #7 lymph node dissection, #8 prognostic factor, #9 prostate cancer, #10 inguinal lymph node dissection, #11 human papillomavirus DNA, #12 gene, #13 penile intraepithelial neoplasia, #14 male sexual function, and #15 penile cancer.

Conclusion

More and more scholars are devoted to the research on penile cancer. This bibliometric analysis revealed that the main research topics and hotspots in penile cancer included risk factors and surgical treatment plans.

Biophysical heterogeneity of myeloid-derived microenvironment to regulate resistance to cancer immunotherapy

Despite the advances in immunotherapy for cancer treatment, patients still obtain limited benefits, mostly owing to unrestrained tumour self-expansion and immune evasion that exploits immunoregulatory mechanisms. Traditionally, myeloid cells have a dominantly immunosuppressive role. However, the complicated populations of the myeloid cells and their multilateral interactions with tumour/stromal/lymphoid cells and physical abnormalities in the tumour microenvironment (TME) determine their heterogeneous functions in tumour development and immune response. Tumour-associated myeloid cells (TAMCs) include monocytes, tumour-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), dendritic cells (DCs), and granulocytes. Single-cell profiling revealed heterogeneous TAMCs composition, sub-types, and transcriptomic signatures across 15 human cancer types. We systematically reviewed the biophysical heterogeneity of TAMC composition and pro/anti-tumoral and immuno-suppressive/stimulating properties of myeloid-derived microenvironments. We also summarised comprehensive clinical strategies to overcome resistance to immunotherapy from three dimensions: targeting TAMCs, reversing physical abnormalities, utilising nanomedicines, and finally, put forward futuristic perspectives for scientific and clinical research.

PD-L1 is associated with the prognosis of penile cancer: A systematic review and meta-analysis

BACKGROUND

Previous studies have explored the role of PD-L1 in the survival outcomes of penile cancer patients with controversies existed. Thus, the meta-analysis was conducted to report and review the association between PD-L1 and survival in penile cancer patients.

METHODS

PubMed, Cochrane Library, EMBASE, and Web of Science were all searched, screened, and reviewed by June 1, 2022. Hazard ratio (HR) was used to evaluate the relationship between PD-L1 and survival outcome, and odds ratio (OR) was for tumor features.

RESULTS

Nine retrospective studies (1,003 patients) were incorporated. The prevalence of PD-L1 in patients with penile cancer was 51.4% (95% CI = 42.1%-60.8%, I 2 = 88.5%). Higher PD-L1 on tumor cells was related to shorter cancer-specific survival (CSS) in patients (HR = 1.578, 95% CI = 1.227-2.029, I 2 = 23.3%), but had no associations with overall survival (OS) (HR = 1.123, 95% CI = 0.511-2.465, I 2 = 0.0%). Subgroup analysis indicated that higher PD-L1 was related to shorter CSS in Caucasus (HR = 1.827, 95% CI = 1.355-2.465, I 2 = 0.0%) only. Furthermore, PD-L1 had associations with tumor stage (pT1 vs. pT2-4, OR = 0.480, 95% CI = 0.346-0.667, P = 0.001) and tumor grade (Well and moderate vs. Poor, OR = 0.377, 95% CI = 0.264-0.538, P < 0.001). PD-L1 positivity was also related to lymph node (LN) status (pN0/NX vs. pN1-3, OR = 0.541, 95% CI = 0.385-0.759, P = 0.001) and HPV status (Positive vs. Negative, OR = 0.510, 95% CI = 0.322-0.810, P = 0.003). A trend toward statistical significance between PD-L1 and histological types was also observed (Usual SCC vs. Others, OR = 1.754, 95% CI = 0.984-3.124, P = 0.070).

CONCLUSIONS

PD-L1 over-expression was related to worse survival outcomes and several clinicopathological features of penile cancer. PD-L1 expression can be applied to select appropriate treatment strategies for penile malignancies.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=343041, identifier CRD42022343041.

Immune landscape and immunotherapy for penile cancer

Penile cancer is a rare malignancy and usually refers to penile squamous cell carcinoma (PSCC), which accounts for more than 95% of all penile malignancies. Although organ-sparing surgery is an effective treatment for early-stage PSCC, surgical intervention alone is often not curative for advanced PSCC with metastases to the inguinal and/or pelvic lymph nodes; thus, systemic therapy is required (usually platinum-based chemotherapy and surgery combined). However, chemotherapy for PSCC has proven to be of limited efficacy and is often accompanied by high toxicity, and patients with advanced PSCC usually have poor prognosis. The limited treatment options and poor prognosis indicate the unmet need for advanced PSCC. Immune-based therapies have been approved for a variety of genitourinary and squamous cell carcinomas but are rarely reported in PSCC. To date, several studies have reported high expression of PDL1 in PSCC, supporting the potential application of immune checkpoint inhibitors in PSCC. In addition, human papillomavirus (HPV) infection is highly prevalent in PSCC and plays a key role in the carcinogenesis of HPV-positive PSCC, suggesting that therapeutic HPV vaccine may also be a potential treatment modality. Moreover, adoptive T cell therapy (ATC) has also shown efficacy in treating advanced penile cancer in some early clinical trials. The development of new therapeutics relies on understanding the underlying biological mechanisms and processes of tumor initiation, progression and metastasis. Therefore, based on the interest, we reviewed the tumor immune microenvironment and the emerging immunotherapy for penile cancer.

Establishment and Characterization of Advanced Penile Cancer Patient-derived Tumor Xenografts: Paving the Way for Personalized Treatments

BACKGROUND

Systemic treatments for penile squamous cell carcinoma (pSCC) are toxic and inefficient. Patient-based preclinical models are essential to study novel treatments.

OBJECTIVE

To establish a library of patient-derived tumor xenograft (PDX) models of human papillomavirus-positive (HPV⁺) and -negative (HPV^-) pSCC and characterize these at the genomic and histological levels.

DESIGN, SETTING, AND PARTICIPANTS

Eighteen tumor samples from 14 patients with recurrent or metastatic pSCC were implanted in nude mice. A biobank of PDX tumors was established after passaging of patient samples (F0) for three generations (F1, F2, F3) and was characterized using histopathology and targeted next-generation sequencing (tNGS). Single-nucleotide polymorphism fingerprinting was used to confirm PDX genealogy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The engraftment rate, overall growth rate, and pSCC histomorphology were checked for each PDX generation. Staining for p40 (a pSCC marker) and p16 (a surrogate for HPV infection) was performed for F0 samples. The mutational profile according to a validated panel of 96 cancer genes was determined for F0 and F3 samples and compared to a larger tNGS database.

RESULTS AND LIMITATIONS

Including a previously established pilot model, 11 out of 18 tumor samples (61%) successfully engrafted in F1. The mean time from implantation in F1 to completion of F3 was 36 wk (standard deviation 18). Histological fidelity was demonstrated across generations. The patient mutational profiles were preserved in F3 and were representative of 277 pSCC samples in the Foundation Medicine database. The rapid progression of pSCC in patients from our selected high-risk cohort impeded the use of PDXs as avatars.

CONCLUSIONS

We successfully established the first library of 11 PDX models of HPV^- and HPV⁺ pSCC. Our PDX models showed high engraftment rates and histological and genomic fidelity to the tumor tissue of origin. These models may help in paving the way towards the development of novel treatments.

PATIENT SUMMARY

We established 11 animal models based on tumor tissue from patients with penile cancer. These models could play a vital role in selection of novel treatments according to genetic mutations. In the future, therapies with confirmed preclinical effects may have a profound impact on the development of personalized treatments in penile cancer.

French AFU Cancer Committee Guidelines - Update 2022-2024: penile cancer

OBJECTIVE

To update French oncology guidelines concerning penile cancer.

METHODS

Comprehensive Medline search between 2020 and 2022 upon diagnosis, treatment and follow-up of testicular germ cell cancer to update previous guidelines. Level of evidence was evaluated according to AGREE-II.

RESULTS

Epidermoid carcinoma is the most common penile cancer histology. Physical examination is mandatory to define local and inguinal nodal cancer stage. MRI with artificial erection can help to assess deep infiltration in cases of organsparing intention. Node negative patients (defined by palpation and imaging) will present micro nodal metastases in up to 25% of cases. Invasive lymph node assessment is thus advocated except for low risk patients. Sentinel node dynamic biopsy is the first line technique. Modified bilateral inguinal lymphadenectomy is an option with higher morbidity. 18-FDG-PET is recommended in patients with palpable nodes. Chest, abdominal and pelvis computerized tomography is an option. Fine needle aspiration (when positive) is an easy way to assess inguinal palpable node pathological involvement. Its results determine the type of lymphadenectomy to be performed (for diagnostic or curative purposes). Treatment is mostly surgical. Free margins status is essential, but it also has to be organ-sparing when possible. Brachytherapy and topic agents can cure in selected cases. Lymph node assessment should be synchronous to the removal of the tumour when possible. Limited inguinal lymph node involvement (pN1 stage) can be cured with the only lymphadenectomy. In case of larger lymph node stage, one should consider multidisciplinary treatment including chemotherapy and inclusion in a trial.

CONCLUSIONS

Penile cancer needs demanding surgery to be cured, surrounded by chemotherapy in node positive patients. Lymph nodes involvement is a major prognostic factor. Thus, inguinal node assessment cannot be neglected.

Metabolic modulation of immune checkpoints and novel therapeutic strategies in cancer

Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) or programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1)-based immune checkpoint inhibitors (ICIs) have led to significant improvements in the overall survival of patients with certain cancers and are expected to benefit patients by achieving complete, long-lasting remissions and cure. However, some patients who receive ICIs either fail treatment or eventually develop immunotherapy resistance. The existence of such patients necessitates a deeper understanding of cancer progression, specifically nutrient regulation in the tumor microenvironment (TME), which includes both metabolic cross-talk between metabolites and tumor cells, and intracellular metabolism in immune and cancer cells. Here we review the features and behaviors of the TME and discuss the recently identified major immune checkpoints. We comprehensively and systematically summarize the metabolic modulation of tumor immunity and immune checkpoints in the TME, including glycolysis, amino acid metabolism, lipid metabolism, and other metabolic pathways, and further discuss the potential metabolism-based therapeutic strategies tested in preclinical and clinical settings. These findings will help to determine the existence of a link or crosstalk between tumor metabolism and immunotherapy, which will provide an important insight into cancer treatment and cancer research.

The prominent role of the S100A8/S100A9-CD147 axis in the progression of penile cancer

Currently, no established biomarkers are recommended for the routine diagnosis of penile carcinoma (PeCa). The rising incidence of this human papillomavirus (HPV)–related cancer entity highlights the need for promising candidates. The Calprotectin subunits S100A8 and S100A9 mark myeloid-derived suppressor cells in other HPV-related entities while their receptor CD147 was discussed to identify patients with PeCa at a higher risk for poor prognoses and treatment failure. We thus examined their expression using immunohistochemistry staining of PeCa specimens from 74 patients on tissue microarrays of the tumor center, the invasion front, and lymph node metastases. Notably, whereas the tumor center was significantly more intensively stained than the invasion front, lymph node metastases were thoroughly positive for both S100 subunits. An HPV-positive status combined with an S100A8+S100A9+ profile was related with an elevated risk for metastases. We observed several PeCa specimens with S100A8+S100A9+-infiltrating immune cells overlapping with CD15 marking neutrophils. The S100A8+S100A9+CD15+ profile was associated with dedifferentiated and metastasizing PeCa, predominantly of HPV-associated subtype. These data suggest a contribution of neutrophil-derived suppressor cells to the progression of HPV-driven penile carcinogenesis. CD147 was elevated, expressed in PeCa specimens, prominently at the tumor center and in HPV-positive PeCa cell lines. CD147+HPV+ PeCa specimens were with the higher-frequency metastasizing cancers. Moreover, an elevated expression of CD147 of HPV-positive PeCa cell lines correlated negatively with the susceptibility to IgA-based neutrophil-mediated tumor cell killing. Finally, stratifying patients regarding their HPV/S100A8/S100A9/CD15/CD147 profile may help identify patients with progressing cancer and tailor immunotherapeutic treatment strategies.

Interplay Between Immune and Cancer-Associated Fibroblasts: A Path to Target Metalloproteinases in Penile Cancer

Extracellular matrix (ECM) remodeling and inflammation have been reported in penile carcinomas (PeCa). However, the cell types and cellular crosstalk involved in PeCa are unexplored. We aimed to characterize the complexity of cells and pathways involved in the tumor microenvironment (TME) in PeCa and propose target molecules associated with the TME. We first investigated the prognostic impact of cell types with a secretory profile to identify drug targets that modulate TME-enriched cells. The secretome analysis using the PeCa transcriptome revealed the enrichment of inflammation and extracellular matrix pathways. Twenty-three secreted factors were upregulated, mainly collagens and matrix metalloproteinases (MMPs). The deregulation of collagens and MMPs was confirmed by Quantitative reverse transcription - polymerase chain reaction (RT-qPCR). Further, the deconvolution method (digital cytometry) of the bulk samples revealed a high proportion of macrophages and dendritic cells (DCs) and B cells. Increased DCs and B cells were associated with better survival. A high proportion of cancer-associated fibroblasts (CAFs) was observed in low-survival patients. Patients with increased CAFs had decreased immune cell proportions. The treatment with the MMP inhibitor GM6001 in CAF cells derived from PeCa resulted in altered cell viability. We reported a crosstalk between immune cells and CAFs, and the proportion of these cell populations was associated with prognosis. We demonstrate that a drug targeting MMPs modulates CAFs, expanding the therapeutic options of PeCa.

Enhancing immune checkpoint blockade therapy of genitourinary malignancies by co-targeting PMN-MDSCs

Immune checkpoint blockade (ICB) as a powerful immunotherapy has transformed cancer treatment. The application of ICB to genitourinary malignancies has generated substantial clinical benefits for patients with advanced kidney cancer or bladder cancer, yet very limited response to ICB therapy was observed from metastatic castration-resistant prostate cancer. The efficacy of ICB in rare genitourinary tumors (e.g. penile cancer) awaits results from ongoing clinical trials. A potential barrier for ICB is tumor-infiltrating polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) with their functions and mechanisms recently revealed. Preclinical studies suggest that successful therapeutic inhibition of PMN-MDSCs synergizes effectively with ICB to eradicate ICB-refractory genitourinary malignancies.

Multi-Omics Profiling to Assess Signaling Changes upon VHL Restoration and Identify Putative VHL Substrates in Clear Cell Renal Cell Carcinoma Cell Lines

The inactivation of von Hippel–Lindau (VHL) is critical for clear cell renal cell carcinoma (ccRCC) and VHL syndrome. VHL loss leads to the stabilization of hypoxia-inducible factor α (HIFα) and other substrate proteins, which, together, drive various tumor-promoting pathways. There is inadequate molecular characterization of VHL restoration in VHL-defective ccRCC cells. The identities of HIF-independent VHL substrates remain elusive. We reinstalled VHL expression in 786-O and performed transcriptome, proteome and ubiquitome profiling to assess the molecular impact. The transcriptome and proteome analysis revealed that VHL restoration caused the downregulation of hypoxia signaling, glycolysis, E2F targets, and mTORC1 signaling, and the upregulation of fatty acid metabolism. Proteome and ubiquitome co-analysis, together with the ccRCC CPTAC data, enlisted 57 proteins that were ubiquitinated and downregulated by VHL restoration and upregulated in human ccRCC. Among them, we confirmed the reduction of TGFBI (ubiquitinated at K676) and NFKB2 (ubiquitinated at K72 and K741) by VHL re-expression in 786-O. Immunoprecipitation assay showed the physical interaction between VHL and NFKB2. K72 of NFKB2 affected NFKB2 stability in a VHL-dependent manner. Taken together, our study generates a comprehensive molecular catalog of a VHL-restored 786-O model and provides a list of putative VHL-dependent ubiquitination substrates, including TGFBI and NFKB2, for future investigation.

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.

The therapeutic implications of immunosuppressive tumor aerobic glycolysis

In 2011, Hanahan and Weinberg added "Deregulating Cellular Energetics" and "Avoiding Immune Destruction" to the six previous hallmarks of cancer. Since this seminal paper, there has been a growing consensus that these new hallmarks are not mutually exclusive but rather interdependent. The following review summarizes how founding genetic events for tumorigenesis ultimately increase tumor cell glycolysis, which not only supports the metabolic demands of malignancy but also provides an immunoprotective niche, promoting malignant cell proliferation, maintenance and progression. The mechanisms by which altered metabolism contributes to immune impairment are multifactorial: (1) the metabolic demands of proliferating tumor cells and activated immune cells are similar, thus creating a situation where immune cells may be in competition for key nutrients; (2) the metabolic byproducts of aerobic glycolysis directly inhibit antitumor immunity while promoting a regulatory immune phenotype; and (3) the gene programs associated with the upregulation of glycolysis also result in the generation of immunosuppressive cytokines and metabolites. From this perspective, we shed light on important considerations for the development of new classes of agents targeting cancer metabolism. These types of therapies can impair tumor growth but also pose a significant risk of stifling antitumor immunity.

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.

DKK1 inhibits canonical Wnt signaling in human papillomavirus-positive penile cancer cells

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Elevated expression of Wnt pathway associated factors in HPV-positive penile cancer cells.

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lacking nuclear beta-catenin translocation indicated an actively abrogated Wnt signaling.

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elevated expression of the Wnt antagonist DKK1 in HPV-positive penile cancer cells.

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DKK1-driven autocrine Wnt pathway inhibition in penile cancer cells.

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DKK1⁺ penile cancers are with a higher frequency HPV⁺, less differentiated and grow more aggressively.

Penile squamous cell cancer (PSCC) is the most frequent penile malignant disease. Infections with human papillomaviruses (HPV) are a major etiologic driver of PSCC. However, the molecular details of the underlying carcinogenesis are understudied because of rare clinical specimens and missing cell lines. Here, we investigated if the expression of high-risk HPV16 oncogenes causes an augmentation of the Wnt pathway using unique HPV-positive penile cancer (PeCa) cell lines in monolayer and organotypic 3D raft cultures as well as tissue micro arrays containing clinical tissue specimens. The HPV oncoproteins enhanced the expression of Leucine-rich repeat-containing G-protein coupled receptor 6 (LGR6) and the HPV-positive PeCa cells expressed a signature of Wnt target and stemness-associated genes. However, the notable lack of nuclear β-catenin in vitro and in situ raised the question if the enhanced expression of Wnt pathway factors is tantamount to an active Wnt signaling. Subsequent TOP-flash reporter assays revealed Wnt signaling as absent and not inducible by respective Wnt ligands in PeCa cell lines. The HPV-positive PeCa cells and especially HPV-positive PeCa specimens of the tumor core expressed the Wnt antagonist and negative feedback-regulator Dickkopf1 (DKK1). Subsequent neutralization experiments using PeCa cell line-conditioned media demonstrated that DKK1 is capable to impair ligand-induced Wnt signaling. While gene expression analyses suggested an augmented and active canonical Wnt pathway, the respective signaling was inhibited due to the endogenous expression of the antagonist DKK1. Subsequent TMA stainings indicated Dkk1 as linked with HPV-positivity and metastatic disease progression in PeCa suggesting potential as a prognostic marker.

Investigation of the Epithelial to Mesenchymal Transition (EMT) Process in Equine Papillomavirus-2 (EcPV-2)-Positive Penile Squamous Cell Carcinomas

Equine penile squamous cell carcinoma (epSCC) is the most frequent tumor of the external male genitalia, representing 67.5% of equine genital cancers. epSCC is associated with papilloma virus (PV) infection and has been recently proposed as a model for human PV-induced squamous cell carcinomas. It has already been suggested that epSCC might undergo epithelial-to-mesenchymal transition (EMT). This work aims to investigate in detail this process and the possible role of PV oncoproteins in epSCC. For this purpose, 18 penile SCCs were retrospectively selected and tested for both EcPV2 presence and oncoproteins (EcPV2 E6 and EcPV2 E7) expression. Moreover, immunohistochemical EMT characterization was carried out by analyzing the main epithelial markers (E-cadherin, β-catenin, and pan-cytokeratin AE3/AE1), the main mesenchymal markers (N-cadherin and vimentin), and the main EMT-related transcription factors (TWIST-1, ZEB-1). PCR analysis was positive for EcPV2 in 16 out of 18 samples. EMT was investigated in epSCC positive for EcPV2. The immunohistochemistry results suggested the presence of EMT processes in the neoplastic cells at the tumor invasive front. Moreover, the significant upregulation of RANKL, together with BCATN1, LEF1, and FOSL1 genes, might suggest a canonical Wnt pathway activation, similarly to what is reported in human penile squamous cell carcinomas

A 25-year perspective on advances in an understanding of the biology, evaluation, treatment and future directions/challenges of penile cancer

Squamous cell carcinoma of the penis (SCCP) is uncommon in some countries (including the U.S.), but is an important malignancy elsewhere. As a rare disease, progress has been slow compared to more common tumor types discussed in this anniversary issue and most often limited to single-center or retrospective datasets.  In this section we describe developments leading to the current standard approach with current research questions.

Recent Advances in the Management of Penile Cancer: A Contemporary Review of the Literature

Penile cancer is a rare condition, which mostly affects men in their sixth decade of life. The most common histology is squamous cell carcinoma (SCC), with about half of the cases linked to human papilloma virus (HPV) infection. The lack of awareness and significant social and psychological stigma associated with penile cancer often leads to delays in presentation, diagnosis and management. Timely multidisciplinary care at experienced centers is therefore critical for improving outcomes. For patients with advanced disease, treatment options are limited and prognosis remains poor. Large international efforts are underway to further define the optimal standards of care. Targeted therapies and immune checkpoint inhibitors could potentially play a role in advanced disease and are under evaluation in clinical trials. In this review, we discuss the current management of penile cancer and future directions.

Pembrolizumab for advanced penile cancer: a case series from a phase II basket trial

BACKGROUND

Treatment options for unresectable, locally advanced or metastatic penile squamous cell carcinoma (SCC) are limited. Previous studies have shown that 40-62% of patients with penile SCC express PD-L1. We report three cases of locally advanced or metastatic penile SCC treated with pembrolizumab.

CASE PRESENTATIONS

Herein, we present three patients with recurrent, locally advanced or metastatic penile SCC who progressed on a platinum-based chemotherapy triplet and were treated with pembrolizumab, administered as part of a phase II clinical trial for rare tumors (NCT02721732). One patient with a microsatellite instability high (MSI-H) tumor experienced a durable partial response to pembrolizumab, underwent surgical consolidation, and remains disease-free 38.7 months later. Two patients experienced progressive disease within 3 months of beginning pembrolizumab. No one experienced a grade 3 or worse treatment-related adverse event.

CONCLUSION

In sum, single-agent pembrolizumab was well tolerated as salvage therapy in a small cohort of patients with unresectable, locally advanced or metastatic penile SCC. Pembrolizumab produced an objective response in an MSI-H tumor, yet it did not control disease in two patients with MSS penile SCC. Rationale combination therapies, including pembrolizumab, warrant further investigation.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02721732 . Registered March 23, 2016.

Experimental Models for Studying HPV-Positive and HPV-Negative Penile Cancer: New Tools for An Old Disease

Simple Summary

Penile cancer is an uncommon and understudied malignancy that is most commonly diagnosed in developing countries. Therapeutic advances have been slow, in part due to the lack of in vitro and in vivo models for testing new drugs before performing clinical trials. Recently, this difficulty has been partly overcome and multiple new pre-clinical models were reported. These important developments will help develop new therapies for penile cancer patients. The present review summarizes and discusses the available data concerning the pre-clinical models of penile cancer and their uses. Comparisons are drawn between different models, allowing researchers to choose the most adequate setting for their experiments. The remaining gaps in this array of penile cancer models are also discussed, in particular the lack of models for studying metastatic disease and cell lines representing tumors associated with human papillomavirus.

Abstract

Penile cancer is an uncommon malignancy that occurs most frequently in developing countries. Two pathways for penile carcinogenesis are currently recognized: one driven by human papillomavirus (HPV) infection and another HPV-independent route, associated with chronic inflammation. Progress on the clinical management of this disease has been slow, partly due to the lack of preclinical models for translational research. However, exciting recent developments are changing this landscape, with new in vitro and in vivo models becoming available. These include mouse models for HPV⁺ and HPV⁻ penile cancer and multiple cell lines representing HPV⁻ lesions. The present review addresses these new advances, summarizing available models, comparing their characteristics and potential uses and discussing areas that require further improvement. Recent breakthroughs achieved using these models are also discussed, particularly those developments pertaining to HPV-driven cancer. Two key aspects that still require improvement are the establishment of cell lines that can represent HPV⁺ penile carcinomas and the development of mouse models to study metastatic disease. Overall, the growing array of in vitro and in vivo models for penile cancer provides new and useful tools for researchers in the field and is expected to accelerate pre-clinical research on this disease.

Case Report: Two Cases of Chemotherapy Refractory Metastatic Penile Squamous Cell Carcinoma With Extreme Durable Response to Pembrolizumab

Background

Penile squamous cell carcinoma (PSCC) is a rare malignancy, and those patients with metastatic disease have limited treatment options. Treatment is largely comprised of platinum-based chemotherapy; however, patients progressing after initial chemotherapy have a median overall survival (OS) of less than 6 months. Based on a high percentage of PD-L1 expression in patients with PSCC, and its biological similarities to other squamous cell carcinomas, we present two patient cases treated with pembrolizumab with extraordinary durable treatment response far beyond treatment with standard therapy.

Main Body

The first patient is a 64 year old male with PSCC who was treated with neoadjuvant chemotherapy, partial penectomy, and adjuvant radiation prior to developing metastatic disease. He had a high TMB (14 mutations/Mb) and was started on pembrolizumab with a complete response, which has been maintained for 38 months. The second patient is an 85 year old male with PSCC who was treated with partial penectomy and adjuvant chemotherapy and radiation prior to developing metastatic disease. He had positive PD-L1 expression CPS 130) and was started on pembrolizumab with a partial response, which has been maintained for 18 months after starting treatment.

Conclusions

These two cases of extreme durable response with pembrolizumab (with molecular data including TMB and PD-L1 status) represent a significant clinical benefit in this patient population. With limited treatment options that result in a median OS of less than 6 months, along with the toxicity profile of chemotherapy which may not be tolerated in elderly patients with comorbidities, this survival benefit with pembrolizumab, along with advances in tumor sequencing and clinical trials shows that there is a potentially significant benefit with novel therapies in this patient population.

The Immune Microenvironment in Penile Cancer and Rationale for Immunotherapy

Penile cancer is an extremely rare malignancy that accounts for approximately 1% of cancer deaths in the United States every year. While primary penile cancer can be managed surgically, advanced and metastatic forms of the disease require more aggressive management plans with systemic chemotherapy and/or radiotherapy. Despite the meaningful response to systemic treatments, the 2-year progression-free survival and disease-specific survival have shown disappointing results. Therefore, there is a crucial need for alternative treatment options with more favorable outcomes and a lower toxicity profile. There are currently extensive studies of tumor molecular biology and clinical trials with targeted molecular therapies, such as PD-1, PD-L1, and CTLA-4. In this review, we will describe the penile cancer microenvironment, and summarize the rationale for immunotherapy in penile cancer patients.

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.

Leveraging innovative therapies with an evolving understanding of the molecular pathogenesis of penile squamous cell carcinoma

Penile squamous cell carcinoma is a rare condition that is associated with significant morbidity and mortality in its advanced stages. In today's rapidly evolving field of oncology, physicians and scientists are learning to harness the power of genomics to drive innovative targeted, immunotherapeutic, and multimodal strategies across different cancer types; however, there remains a pressing need for a deeper understanding of the molecular pathways of penile carcinogenesis in order to help direct individualized therapy for patients with this disease. In this article, we will review our current understanding of some of the biologic mechanisms, including virally and nonvirally based pathways, which are thought to drive the development and progression of penile cancer.