Identification and genotyping of human papillomavirus in a Spanish cohort of penile squamous cell carcinomas: Correlation with pathologic subtypes, p16INK4a expression, and prognosis

High-risk human papilloma virus status & outcomes for penile squamous cell carcinoma: A single institution experience

OBJECTIVES

There is a paucity of data on North American cohorts of patients with penile squamous cell carcinoma (pSCC). Herein, we aimed to assess the sensitivity of various modalities to identify human papillomavirus (HPV) status, determine the prevalence of high-risk HPV-positivity, and evaluate the prognostic impact of relevant clinicopathologic variables.

METHODS

Patients with pSCC (n = 121) consecutively treated with partial/total penectomy (2000-2022) at a single institution were included. HPV status (based on immunohistochemistry [IHC], in situ hybridization [ISH], and panviral metagenomic sequencing [PMS]), histologic features, and outcomes were reviewed. Outcome events included death due to disease and progression.

RESULTS

The majority of patients were white (105/121, 86.8%). Thirty-seven (30.6%) were high-risk HPV-positive, and morphologic evaluation had a sensitivity of 97.3% (95% confidence interval [CI], 86.2-99.5) for predicting high-risk HPV status compared to IHC/ISH/PMS. Disease progression was more common among high-risk HPV-negative compared to high-risk HPV-positive patients (HR 2.74, CI 1.12-8.23, P = 0.03). Moreover, among high-risk HPV-negative patients, those with moderate-poorly differentiated tumors had increased disease-specific mortality (32.6%, CI 17.1-48.1) compared to those with well-differentiated tumors (0%). Among high-risk HPV-positive patients, those with basaloid morphology had lower disease-specific mortality (0% vs 14.4%, CI 0.0-33.1).

CONCLUSIONS

We demonstrate high-risk HPV-positivity in approximately one-third of patients with pSCC. Morphologic evaluation alone had a high sensitivity in correctly determining HPV status. Our results suggest that high-risk HPV status and morphologic features (differentiation in high-risk HPV-negative, and basaloid subtype in high-risk HPV-positive pSCC) may have prognostic value.

The Prognostic Value of Human Papillomavirus Status in Penile Cancer: Outcomes From a Norwegian Cohort Study

INTRODUCTION

Penile squamous cell carcinoma (PSCC) can develop from human papillomavirus (HPV) infection. This study investigates if the prognostic value of the TNM stage groups or the components tumor stage (pT), grade of differentiation (Grade), lymphovascular invasion (LVI), and nodular stage (pN) depend on HPV status. Also, whether the value of tumor parameters (pT, Grade, and LVI) for predicting node-positive disease depends on HPV status was investigated.

PATIENTS AND METHODS

Stored tumor tissue from 226 patients treated for PSCC in Western Norway between 1973 and 2023 was investigated for HPV DNA. Histopathological variables were reevaluated according to the current TNM classification. Disease course was registered from hospital records. Inclusion of an interaction term between HPV and TNM stage groups in Cox regression enabled analysis of whether cancer-specific survival (CSS) of the stage groups depended on HPV status. This was also done separately for pT, Grade, LVI, and pN. Logistic regression with interaction terms between HPV and the tumor parameters were used to investigate if their predictive value depended on HPV status.

RESULTS

HPV DNA was detected in 43% of the tumors. Stratified by HPV status, there was no significant interaction term in the Cox regression between HPV status and TNM stage groups (P = .74). Similar results were found for pT (P = .94), Grade (P = .08), LVI (P = .91) and pN (P = .77). Moreover, there were no significant interaction terms in the logistic regression between HPV status and the tumor parameters pT, Grade, and LVI (all P > .2).

CONCLUSIONS

This study found that prognosis of the TNM stage groups and the components pT, Grade, LVI, and pN were not modified by HPV in PSCC. The value of pT, Grade, and LVI for predicting lymph node-positive disease was not affected by HPV status.

The Prognostic Role of Human Papillomavirus and p16 Status in Penile Squamous Cell Carcinoma-A Systematic Review

PSCC is a rare cancer, with approximately half of all cases related to HPV. While HPV and p16 IHC testing have proven their prognostic value for oropharyngeal cancer, this is not yet established for PSCC. The current level of evidence exploring the relation between PSCC and HPV is moderate, so we conducted a systematic review following PRISMA guidelines to evaluate the prognostic role of HPV and p16 IHC in PSCC clinical outcomes. We searched the PubMed, Embase, and Cochrane databases and identified 34 relevant studies that met our inclusion criteria. Of these, 33 were retrospective cohort studies, and one was a cross-sectional study. Nine studies reported that HPV-positive and p16-positive PSCC had better overall survival (OS) and disease-free survival (DFS). This study highlights the need for a meta-analysis to determine the role of routine HPV status or p16 staining testing as part of the initial diagnosis and staging of PSCC patients worldwide.

Immune cell infiltration, tumour budding, and the p53 expression pattern are important predictors in penile squamous cell carcinoma: a retrospective study of 152 cases

Penile squamous cell carcinoma (pSCC) is a rare malignancy with a slowly increasing incidence and variable prognosis. Regional lymph node involvement signifies poor prognosis but represents a late sign, and more prognostic markers for effective patient risk stratification are urgently needed. In this retrospective study, 152 tumour samples with formalin-fixed, paraffin-embedded tissue were analysed for traditional pathological variables, tumour budding, p53, p16, and mismatch repair proteins (MMR) immunohistochemistry. The density of tumour lymphocytic infiltrate was also determined, using subjective evaluation by two pathologists (brisk/non-brisk/absent) and also using the immunoscore method, which categorised the cohort into five immunoscore groups according to the number of CD3+ and CD8+ T-cells in both the tumour centre and tumour invasion front. Only one case (0.6%) was MMR-deficient. Tumour budding count ≥5 tumour buds/20× power field and non-brisk/absent lymphocytic infiltrate were significant negative predictors of both the overall survival (OS) and cancer-specific survival (CSS), whereas a low immunoscore was a significant marker of shorter OS but not CSS. Advanced pT stage (3+4) was a significant marker of shorter CSS but not OS. In the multivariate analysis, high-grade budding was a significant parameter if adjusted for the patient's age and associated variables, except for the pN stage. The lymphocytic infiltrate retained its prognostic significance if adjusted for age and associated variables. The negative prognostic significance of the previously described parameters (lymphatic, venous, and perineural invasion, regional lymph node metastasis, and p53 mutated profile) were confirmed in our study. Grade, histological subtype, and HPV status (as determined by p16 immunohistochemistry) showed, surprisingly, little or no prognostic significance.

Penile squamous cell carcinoma exclusive to the shaft, with a proposal for a novel staging system

Penile squamous cell carcinomas (SCC) originating in the shaft are rare. pT1/pT2 categories in the American Joint Committee on Cancer (AJCC) staging manual (8th edition) are poorly defined for SCCs arising in the dorsal shaft as anatomic structures differ between the glans and dorsal shaft (corpus spongiosum vs dartos/Buck's fascia, respectively). We reviewed six penile SCC cases exclusive to the shaft, an unusual presentation, identified amongst 120 patients treated with penectomy. We propose a novel pT staging system for dorsal shaft tumors tailored to its anatomic landmarks, where tumors extending to Buck's fascia are considered pT2 instead of pT1. The mean age at penectomy, average duration of follow-up, and mean depth of invasion were 64 years, 45 months, and 9.8 mm, respectively. Four cases were moderately differentiated, HPV-negative SCCs of the usual type and two cases were HPV-positive basaloid and warty-basaloid carcinomas. Three cases had nodal or distant metastasis at the time of penectomy, and histologic assessment in these cases showed invasion into the Buck's fascia or deeper. According to the current AJCC system, only one of these three cases would be staged as ≥ pT2. In contrast, all three metastatic tumors would be staged as ≥ pT2 in the proposed model. At last follow-up, one patient died of disease-related complications. Based on this limited series, the proposed staging model appears to suggest better patient stratification for pT1/pT2 stages. This model incorporates Buck's fascia, which has been postulated as a pathway of tumor infiltration. Additional studies are needed to validate this model.

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.

Penile Squamous Cell Carcinomas in Sub-Saharan Africa and Europe: Differential Etiopathogenesis

Penile squamous cell carcinomas (PSCC) are classified by the World Health Organization into two categories based on their relationship with the human papillomavirus (HPV): HPV-associated and HPV-independent. We compared a cohort of PSCC from Mozambique, a sub-Saharan country in southeast Africa with a high prevalence of HPV and HIV infection, and Spain, a country in southwestern Europe with a low prevalence of HPV and HIV, to study the distribution of the etiopathogenic categories of these tumors in both sites. A total of 79 PSCC were included in the study (28 from Mozambique and 51 from Spain). All cases underwent HPV-DNA polymerase chain reaction (PCR) testing, genotyping, and immunohistochemistry for p16 and p53. Any PSCC showing either p16 overexpression or HPV-DNA in PCR analysis was considered HPV-associated. Overall, 40/79 (50.6%) tumors were classified as HPV-associated and 39 (49.4%) as HPV-independent. The two sites showed marked differences: 25/28 (89.3%) tumors from Mozambique and only 15/51 (29.4%) from Spain were HPV-associated (p < 0.001). HPV16 was the most frequent HPV type identified in 64.0% (16/25) of the HPV-associated tumors from Mozambique, and 60.0% (9/15) from Spain (p = 0.8). On average, patients from Mozambique were almost two decades younger than those from Spain (mean age 50.9 ± 14.9 and 69.2 ± 13.3, respectively [p < 0.001]). In conclusion, significant etiopathogenic differences between PSCC in Mozambique and Spain were observed, with a remarkably high prevalence of HPV-associated tumors in Mozambique and a relatively low prevalence in Spain. These data may have important consequences for primary prevention of PSCC worldwide.

An update on treatment of penile cancer

Penile cancer is a rare malignancy, particularly in industrialized nations. In the United States, rates are approximately less than 1 per 100,000 men per year with just over 2000 new cases per year. However, there is significantly increased prevalence in developing nations, with limited treatment expertise and reduced access to care, further driving an unmet clinical need. The most noteworthy risk factor for penile cancer is the association with human papillomavirus infection, which may be present in up to 50% of all penile carcinomas. In addition to local primary tumor approaches, multimodality treatment strategies are vital to patients with clinical regional nodal disease, locally advanced disease. Presence and degree of lymph node involvement remains the most important prognostic factor and patients may benefit from multiple treatment strategies. Interim analysis data from the first randomized clinical trial is expected to yield results in mid/late 2024–early 2025. These treatment approaches include neoadjuvant chemotherapy, adjuvant therapy, including chemotherapy and radiation. Systemic therapy for distant recurrent or metastatic disease is primarily a platinum-based chemotherapy, however with poor overall response. As poor outcomes remain high, particularly in indigent populations, there remains an unmet need for these patients, particularly for high level randomized trials and novel therapeutics. In this review, we will highlight treatment updates for penile cancer. In addition to standard of care, we will review novel lines of therapies including immunotherapies and targeted therapies as well as sequencing approaches.

Immunotherapeutic Approaches for the Treatment of HPV-Associated (Pre-)Cancer of the Cervix, Vulva and Penis

Human papillomavirus (HPV) infection drives tumorigenesis in almost all cervical cancers and a fraction of vulvar and penile cancers. Due to increasing incidence and low vaccination rates, many will still have to face HPV-related morbidity and mortality in the upcoming years. Current treatment options (i.e., surgery and/or chemoradiation) for urogenital (pre-)malignancies can have profound psychosocial and psychosexual effects on patients. Moreover, in the setting of advanced disease, responses to current therapies remain poor and nondurable, highlighting the unmet need for novel therapies that prevent recurrent disease and improve clinical outcome. Immunotherapy can be a useful addition to the current therapeutic strategies in various settings of disease, offering relatively fewer adverse effects and potential improvement in survival. This review discusses immune evasion mechanisms accompanying HPV infection and HPV-related tumorigenesis and summarizes current immunotherapeutic approaches for the treatment of HPV-related (pre-)malignant lesions of the uterine cervix, vulva, and penis.

p53 and p16ink4a As Predictive and Prognostic Biomarkers for Nodal metastasis and Survival in A Contemporary Cohort of Penile Squamous Cell Carcinoma

BACKGROUND

Human papilloma virus (HPV) infection is implicated in a proportion of invasive squamous cell carcinoma of the penis (PC). A subset of PC involves dysregulation of the p53 pathway. HPV in situ hybridization (ISH) and p16^ink4a positivity are surrogate markers for HPV infection, and p53 immunohistochemistry (IHC) denotes abnormality in the p53 pathway. There remains an ambiguity with regard to the contribution of both the pathways in the prognosis of PC. We sought to analyze the clinicopathologic characteristics of a cohort of Indian PC patients with respect to p16 ^ink4a and p53 expression.

PATIENTS AND METHODS

A cohort of 123 PC patients was studied for p16^ink4aand p53IHC and HPVISH. The results of these biomarkers were correlated with various clinicopathologic parameters.

RESULTS

p16^ink4a and HPV ISH were positive in 47% and 53% of the tumors, respectively. The proportion of warty, basaloid, or mixed warty-basaloid tumor subtypes showed significant p16^ink4apositivity (P < .0001) compared to other subtypes. Twenty-eight patients were dual negative (p53- /p16^ink4a-), 32 were dual positive (p53+/p16^ink4a+), 38 were p53+/p16^ink4a-, and 25 were p53-/p16^ink4a +. In patients where p16^ink4a was negative, a p53-positive phenotype had a higher propensity for lymph node metastases (OR, 5.42; 95% CI, 1.75-16.80; P = .003). Similarly, p53 positivity dictates nodal involvement in the p16^ink4a-positive subset of tumors (OR, 5.00; 95% CI, 1.23-20.17; P = .024). On multivariate analyses, pathologic subtypes (warty, warty-basaloid, and basaloid) (P < .0001), p16^ink4aexpression (P < .0001), and absence of nodal metastasis (P < .0001) were significant predictors of improved overall (OS) and cancer specific survival (CSS). In Kaplan-Meier analysis, the OS was significantly longer in patients with p16^ink4a + tumors (P < .0001), as was the CSS (P < .0001). Patients with dual positive tumors had a significantly higher OS (P < .001) and CSS (P = .012), in the entire cohort. In the node positive patients, dual positivity was associated with significantly higher OS (P < .0001); however, the median CSS for p53+/p16^ink4a+tumors were not significantly different compared to p53- /p16^ink4a- tumors (P = .064), although there was a trend towards improved CSS.

CONCLUSIONS

There is a strong concordance between p16^ink4aIHC and HPV ISH results. p16^ink4a status is an independent predictor of survival (OS and CSS) in our cohort of PCs. p53 is a predictor of nodal metastasis irrespective of p16 status. Dual positive tumors have a significantly better outcome in comparison to dual negative tumors.

[Conventional grading vs. molecular grading : Decision aids for clinical routine]

Conventional histopathological grading of a cancer is of utmost importance for the management and prognosis of the patient. Histopathological grading is predominantly a function of the differentiation and proliferation of tumor cells, the amount of necrosis present and the pattern of invasion. In addition, the molecular set-up of a given cancer which can be determined to some degree by immunohistochemistry or by methods analyzing genetic and epigenetic alterations can be used in some instances to improve the information gained by conventional histopathologic grading. Indeed, this latter option implies the promise of individualized tumor therapy. While this promise is on the horizon, the clinical implications for penile cancer are not yet transferable to individualized penile cancer treatment.

Distinct Patterns of Myeloid Cell Infiltration in Patients With hrHPV-Positive and hrHPV-Negative Penile Squamous Cell Carcinoma: The Importance of Assessing Myeloid Cell Densities Within the Spatial Context of the Tumor

Comprehensive analysis of tumor infiltrating myeloid cells in the tumor microenvironment of penile squamous cell carcinoma (PSCC) is lacking. In this retrospective study, for the first time, PSCC resection specimens (N = 103) were annotated into the following compartments: intratumoral tumor (IT Tumor), intratumoral stroma (IT Stroma), peritumoral tumor (PT Tumor) and peritumoral stroma (PT Stroma) compartments. We then quantified CD14+, CD68+ and CD163+ myeloid cells within these compartments using an image analysis software and assessed their association with various clinical parameters, including high-risk human papillomavirus (hrHPV) status. In the total cohort, hrHPV status, grade of differentiation, age and tumor size were associated with myeloid cell densities. hrHPV⁺ tumors had higher infiltration rates of CD14+, CD68+ and CD163+ myeloid cells in the IT tumor compartment (p < 0.001, for all) compared to hrHPV^- tumors. Furthermore, when examining the association between compartment-specific infiltration and differentiation grade, increased myeloid cell densities in the IT tumor compartment were associated with a more advanced histological grade (p < 0.001, for all). This association remained significant when the hrHPV^- cohort (N = 60) was analyzed (CD14+ p = 0.001; CD68+ p < 0.001; CD163+ p = 0.004). Subgroup analysis in the hrHPV⁺ group (N = 43) showed that high infiltration rates of CD68+ and CD163+ cells in the PT tumor compartment were associated with lymph node (LN) metastasis (p = 0.031 and p = 0.026, respectively). Regarding the association between myeloid cell densities and disease-specific survival, the risk of death was found to decrease slightly as the number of myeloid cells in the IT tumor compartment increased (CD14+ p = 0.04; CD68+ p = 0.05; CD163+ p = 0.02). However, after adjusting for hrHPV, no independent association between myeloid densities and disease-specific survival were found. Altogether, these findings demonstrate the importance of assessing myeloid cell densities within the spatial context of the tumor. Further studies are needed to unravel the specific phenotype of myeloid cells residing in the different compartments, their effect on clinical parameters and the impact of hrHPV on the recruitment of myeloid cell populations in PSCC.

Discrepancy of p16 immunohistochemical expression and HPV RNA in penile cancer. A multiplex in situ hybridization/immunohistochemistry approach study

Background

The high-risk human papillomavirus (HPV) infection represents one of the main etiologic pathways of penile carcinogenesis in approximately 30–50 % of cases. Several techniques for the detection of HPV are currently available including Polymerase chain reaction-based techniques, DNA and RNA in situ hybridization (ISH), p16 immunohistochemistry (IHC). The multiplex HPV RNA ISH/p16 IHC is a novel technique for the simultaneous detection of HPV E6/E7 transcripts and p16INK4a overexpression on the same slide in a single assay. The main aim of this study was to evaluate the discrepancy of p16 IHC expression relatively to HPV RNA ISH in penile cancer tissue.

Methods

We collected a series of 60 PCs. HPV has been analysed through the RNA ISH, p16 IHC and the multiplex HPV RNA ISH/p16 IHC.

Results

The multiplex HPV RNA ISH /p16 IHC results in the series were in complete agreement with the previous results obtained through the classic p16 IHC and HPV RNA scope carried out on two different slides. The multiplex HPV RNA ISH /p16 IHC showed that HPV positivity in our series is more frequently in usual squamous cell carcinoma than in special histotypes (19 out of 60 − 15 %- versus 6 out of 60 − 10 %-), in high-grade than in moderate/low grade carcinomas (6 out of 60 − 10 %- versus 4 out of 60 − 6.7 %-). In addition, our data revealed that in 5 out of 20 cases with p16 high intensity expression is not associated with HPV RNA ISH positivity.

Conclusions

Our findings emphasize that the use of p16 as a surrogate of HPV positivity was unsuccessful in approximatively 8 % of cases analysed in our series. Indeed, p16 IHC showed a sensitivity of 100 % and a specificity of 71 %, with a positive predictive value (PPV) of 54 % and a negative predictive value of 100 %; when considering high intensity, p16 IHC showed a sensitivity of 100 %, a specificity of 89 %, with a PPV of 75 % and NPV of 100 %.

Since HPV positivity could represent a relevant prognostic and predictive value, the correct characterization offered by this approach appears to be of paramount importance.

The prevalence of human leucocyte antigen and human papillomavirus DNA in penile intraepithelial neoplasia in England 2011-2012

BACKGROUND

The pathogenesis of penile intraepithelial neoplasia (PeIN) is unclear but human papillomavirus (HPV) infection and polymorphisms in human leucocyte antigen (HLA).

OBJECTIVES

To examine the prevalence of HPV DNA and HLA in PeIN.

METHODS

Adult Caucasian men with a clinical and histological diagnosis of PeIN, that is, Bowenoid papulosis (BP), Bowen's disease of penis (BDP) and erythroplasia of Queyrat (EQ) were selected and phenotyped from the clinical records. DNA was extracted from blood and paraffin-embedded sections for HLA and HPV typing, respectively. Human leucocyte antigen allele frequencies were compared with those derived from the UK-based Caucasian population.

RESULTS

Seventy-two cases of PeIN (20 BP, 34 BDP and 18 EQ) were studied. Human papillomavirus DNA was identified in 65/72 (90.2%) PeIN; Alphapapillomavirus types were detected in 62/72 (85%) followed by Betapapillomavirus types in 9/72 (12.5%) and cutaneous types in 7/72 (9.7%); HPV16 was the most prevalent genotype at 35/72 (48.6%) followed by HPV33 at 7/72 (9.7%); multiple infections were seen in 18/72 (25%) PeIN. HLA-C*15 (Bonferroni corrected p = 0.049) confers susceptibility to PeIN, whereas HLA-DQA1*01 (corrected p = 0.02) protects against PeIN. HPV16-associated PeIN cases showed no statistically significant association with HLA genotype after multiple corrections.

CONCLUSION

Human papillomavirus is involved in the pathogenesis of PeIN. Immunogenotype may play a role in the pathogenesis of PeIN.

Improving five-year survival prediction via multitask learning across HPV-related cancers

Oncology is a highly siloed field of research in which sub-disciplinary specialization has limited the amount of information shared between researchers of distinct cancer types. This can be attributed to legitimate differences in the physiology and carcinogenesis of cancers affecting distinct anatomical sites. However, underlying processes that are shared across seemingly disparate cancers probably affect prognosis. The objective of the current study is to investigate whether multitask learning improves 5-year survival cancer patient survival prediction by leveraging information across anatomically distinct HPV related cancers. Data were obtained from the Surveillance, Epidemiology, and End Results (SEER) program database. The study cohort consisted of 29,768 primary cancer cases diagnosed in the United States between 2004 and 2015. Ten different cancer diagnoses were selected, all with a known association with HPV risk. In the analysis, the cancer diagnoses were categorized into three distinct topography groups of varying specificity. The most specific topography grouping consisted of 10 original cancer diagnoses differentiated by the first two digits of the ICD-O-3 topography code. The second topography grouping consisted of cancer diagnoses categorized into six distinct organ groups. Finally, the third topography grouping consisted of just two groups, head-neck cancers and ano-genital cancers. The tasks were to predict 5-year survival for patients within the different topography groups using 14 predictive features which were selected among descriptive variables available in the SEER database. The information from the predictive features was shared between tasks in three different ways, resulting in three distinct predictive models: 1) Information was not shared between patients assigned to different tasks (single task learning); 2) Information was shared between all patients, regardless of task (pooled model); 3) Only relevant information was shared between patients grouped to different tasks (multitask learning). Prediction performance was evaluated with Brier scores. All three models were evaluated against one another on each of the three distinct topography-defined tasks. The results showed that multitask classifiers achieved relative improvement for the majority of the scenarios studied compared to single task learning and pooled baseline methods. In this study, we have demonstrated that sharing information among anatomically distinct cancer types can lead to improved predictive survival models.

PD1/PD-L1 Axis in Uro-oncology

The immune system is important to control tumor development and progression in humans. However, tumor cells and cells of the tumor microenvironment can induce immune escape mechanisms including activation of immune checkpoints such as PD-1/PD-L1. Based on this knowledge, new immune therapies, including PD-1 and PD-L1 inhibition, have been developed and are already recommended as a standard treatment in metastatic bladder and kidney cancer patients. In addition to its role as a therapeutic target, PD-L1 seems to be a prognostic parameter although data are controversial. Only little is known about signaling pathways inducing PD-L1 expression in tumor cells on one hand and about its functional role for tumor cells itself. However, the understanding of the complex biological function of PD-L1 will improve therapeutic options in urological malignancies. This review is giving an overview of the current knowledge concerning the PD-1/PD-L1 axis in urological tumors including bladder, kidney, prostate, testicular and penile cancer.

Prevalence of human papillomavirus and implication on survival in Chinese penile cancer

We assessed the prevalence of HPV DNA in a large series of Chinese penile cancer and examine its association with the histological subtype, p16^INK4a expression, and prognosis. We pathologically categorized 226 invasive penile squamous cell carcinomas and assessed HPV genotyping by real-time PCR and p16^INK4a immunohistochemistry. The results were correlated with histopathological and clinical parameters and disease-specific survival (DSS). HPV DNA was detected in 32.7% (74/226) of penile cancer cases. The most frequent genotype was HPV 16 (64/74, 86.5%), followed by HPV 18 (6/74, 8.1%). Fifty-nine (26.1%) cases were positive for the p16^INK4a expression, and p16^INK4a expression had a sensitivity of 56.8% (95% CI, 45.2-68.3%) and a specificity of 88.8% (95% CI, 83.8-93.9%) for defining HPV status. HPV DNA (P = 0.019), p16^INK4a (P = 0.038), age (P = 0.018), grade of differentiation (P = 0.001), lymph nodes (P < 0.001), T stage (P < 0.001), M stage (P < 0.001), and lymphovascular invasion (LVI, P = 0.001) were prognostic factors for DSS. HPV-positivity (HR 0.334; 95% CI, 0.158-0.705, P = 0.004) was still a significant prognostic factor for DSS in the multivariate Cox regression model. HPV DNA was observed in one third of Chinese penile carcinoma cases. The p16INK4a expression can indicate high-risk human papillomavirus (HR-HPV). HPV-positive penile tumors confer a survival benefit over HPV-negative tumors.

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.

Single-Center Analysis of Human Papillomavirus Infection and P16INK4A Expression among Korean Patients with Penile Cancer

Purpose

This study aimed to evaluate the statuses of P16INK4A expression and human papillomavirus (HPV) infection among patients with penile cancer at a single Korean institution.

Patients and Methods

Fourteen patients with penile cancer at our center were retrospectively identified and their clinicopathological data were analyzed. The patients' HPV and P16INK4A expression status (a known tumor suppressor protein) were tested using genotyping with a DNA chip assay and immunohistochemical staining, respectively. The results regarding HPV status were compared to those from another Asian study.

Results

The mean age at diagnosis was 60 years (range: 34–86 years). The median tumor size was 3.0 cm (range: 0.6–4.7 cm). Ten tumors were located on the penile glans. Five patients tested positive for HPV DNA (5/14, 36%) and all cases involved HPV type 16 (5/5, 100%). Positive expression of P16INK4A was observed in 6 cases (6/14, 43%). Among the HPV positive cases, 80% of cases (4/5) were also positive for P16INK4A. The prevalence of HPV infection in our study (36%) was higher than in a previous Asian study (23%).

Conclusions

This is the first study to evaluate the prevalence of HPV infection and P16INK4A expression among patients with penile cancer at a single Korean institution. The prevalence of HPV (36%) was slightly higher than the results from a previous Asian study. Additional multi-center studies are needed to better understand penile cancer in Korea and to identify biomarkers that can determine high-risk cases and predict their prognosis.

P16INK4a expression in patients with penile cancer

BACKGROUND

Infection with human papillomavirus (HPV) is reported to be present in 30-50% of penile cancer cases. The immunohistochemical test for p16INK4a is used as an indicator of the presence of HPV and as a prognostic marker for squamous cell carcinomas in various sites. However, the role of this marker in penile carcinoma has not yet been completely elucidated. The aim of this study was to analyze whether the expression of p16INK4a is associated with the presence of HPV, histological parameters, and survival in penile cancer.

METHODS

A study was conducted from 2014 to 2016 that included 55 patients with penile carcinoma. HPV DNA was detected through PCR using fresh tumor tissue, and immunohistochemistry was performed for analysis of p16INK4a protein using paraffin-embedded tissue. Evaluation of histological parameters was performed following complete embedding of the tumor tissue in paraffin.

RESULTS

HPV DNA (low-risk and high-risk genotypes) was found in 49 (89.1%) cases, and 46/49 (93.9%) showed high-oncogenic risk HPV (HR-HPV). Of the 22 cases positive for p16INK4a, HR-HPV DNA was present in 21 (95.5%) (p = 0.032). Regarding histological parameters, p16INK4a and HR-HPV were significantly associated only with tumor subtype (p = 0.036 and p = 0.032, respectively); all carcinomas with basaloid characteristics were positive for p16INK4a. Although HPV+ patients had a higher disease-free survival (p <0.001), p16INK4a expression was not associated with patient survival.

CONCLUSIONS

Our study, using fresh tissue samples, showed the highest incidence of HPV compared to that observed in the literature. Expression of the p16INK4a protein was significantly associated with the presence of HR-HPV and this expression may serve as a marker for the presence of the virus. The p16INK4a protein was not associated with the histological prognostic parameters, with the exception of tumor subtype, nor with patient survival. In the results, we showed that the objective of the present study was reached.

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.

Prognostic Significance of P16INK4a Expression in Penile Squamous Cell Carcinoma: A Meta-Analysis with Trial Sequential Analysis

Background

Recently, P16^INK4a expression has been shown to be correlated with cancer-specific survival (CSS) in penile squamous cell carcinoma (SCC). Therefore, we performed this meta-analysis to clarify the prognostic value of P16^INK4a for penile SCC.

Methods

A systematic search was performed in PubMed, Embase, and Web of Science to identify all relevant articles up to May 25, 2017. Hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) of included studies were pooled to estimate the prognostic value. Trial sequential analysis (TSA) was performed to assess the quantity and strength of survival evidence.

Results

Five retrospective studies consisting of 323 cases were finally included. We found that P16^INK4a positive expression was significantly associated with a better CSS of penile SCC (HR=0.45, 95%CI: 0.30-0.67, P<0.001). No heterogeneity or publication bias was noted among the included studies. Furthermore, TSA demonstrated that the findings were based on sufficient evidence.

Conclusions

P16^INK4a positive expression is independently associated with improved CSS for patients with penile SCC.

Human papillomavirus (HPV) genotype distribution in penile carcinoma: Association with clinic pathological factors

Background

Penile carcinoma (PC) is a rare, highly mutilating disease, common in developing countries. The evolution of penile cancer includes at least two independent carcinogenic pathways, related or unrelated to HPV infection.

Objectives

To estimate the prevalence, identify HPV genotypes, and correlate with clinicopathological data on penile cancer.

Methods

A retrospective cohort study involving 183 patients with PC undergoing treatment in a referral hospital in Goiânia, Goiás, in Midwestern Brazil, from 2003 to 2015. Samples containing paraffin embedded tumor fragments were subjected to detection and genotyping by INNO-LiPA HPV. The clinicopathological variables were subjected to analysis with respect to HPV positivity and used prevalence ratio (PR), adjusted prevalence ratio (PRa) and 95% confidence interval (CI) as statistical measures.

Results

The prevalence of HPV DNA in PC was 30.6% (95% CI: 24.4 to 37.6), high-risk HPV 24.9% (95% CI: 18.9 to 31.3), and 62.5% were HPV 16. There was a statistical association between the endpoints HPV infection and HPV high risk, and the variable tumor grade II-III (p = 0.025) (p = 0.040), respectively. There was no statistical difference in disease specific survival at 10 years between the HPV positive and negative patients (p = 0.143), and high and low risk HPV (p = 0.325).

Conclusions

The prevalence of HPV infection was 30.6%, and 80.3% of the genotypes were identified as preventable by anti-HPV quadrivalent or nonavalent vaccine. HPV infections and high-risk HPV were not associated with penile carcinoma prognosis in this study.

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.

Insight into novel biomarkers in penile cancer: Redefining the present and future treatment paradigm?

INTRODUCTION

Biomarkers are increasingly used in the diagnosis and management of various malignancies. Selected biomarkers may also play a role in management of certain cases of penile carcinoma. In this article, we provide an overview of the clinical role of such markers in the management of penile cancer.

METHOD

This is a nonsystematic review of relevant literature assessing biomarkers in penile carcinoma.

RESULTS

Evidence of infections with human papillomavirus and its surrogate markers may have important prognostic value in patients with localized or metastatic penile cancer. Squamous cell carcinoma antigen, p53, C-reactive protein, Ki-67, proliferating cell nuclear antigen, cyclin D1, as well as other markers have been studied with various degree of evidence in support of clinical utility in penile cancer.

CONCLUSIONS

No single marker may have all the answers, and future research should focus on genomic analysis of individual penile tumors, attempting to identify specific targets for treatment.

Human Papillomavirus (HPV) Genotypes in Condylomas, Intraepithelial Neoplasia, and Invasive Carcinoma of the Penis Using Laser Capture Microdissection (LCM)-PCR: A Study of 191 Lesions in 43 Patients

Laser capture microdissection-polymerase chain reaction (LCM-PCR) supported by p16 was used for the first time to demonstrate human papillomavirus (HPV) DNA in histologically specific penile lesions, which were as follows: squamous hyperplasia (12 lesions, 10 patients), flat lesions (12 lesions, 5 patients), condylomas (26 lesions, 7 patients), penile intraepithelial neoplasia (PeIN) (115 lesions, 43 patients), and invasive squamous cell carcinomas (26 lesions, 26 patients). HPV was detected by whole-tissue section and LCM-PCR. LCM proved to be more precise than whole-tissue section in assigning individual genotypes to specific lesions. HPV was negative or very infrequent in squamous hyperplasia, differentiated PeIN, and low-grade keratinizing variants of carcinomas. HPV was strongly associated with condylomas, warty/basaloid PeIN, adjacent flat lesions, and warty/basaloid carcinomas. A single HPV genotype was found in each lesion. Some condylomas and flat lesions, especially those with atypia, were preferentially associated with high-risk HPV. Unlike invasive carcinoma, in which few genotypes of HPV were involved, there were 18 HPV genotypes in PeIN, usually HPV 16 in basaloid PeIN but marked HPV heterogeneity in warty PeIN (11 different genotypes). Variable and multiple HPV genotypes were found in multicentric PeIN, whereas unicentric PeIN was usually related to a single genotype. There was a correspondence among HPV genotypes in invasive and associated PeIN. p16 was positive in the majority of HPV-positive lesions except condylomas containing LR-HPV. p16 was usually negative in squamous hyperplasia, differentiated PeIN, and low-grade keratinizing variants of squamous cell carcinomas. In summary, we demonstrated that LCM-PCR was a superior research technique for investigating HPV genotypes in intraepithelial lesions. A significant finding was the heterogeneity of HPV genotypes in PeIN and the differential association of HPV genotypes with subtypes of PeIN. The presence of atypia and high-risk HPV in condylomas and adjacent flat lesions suggests a precursor role, and the correspondence of HPV genotypes in invasive carcinomas and associated PeIN indicates a causal relation. Data presented support the bimodal hypothesis of penile cancer carcinogenesis in HPV-driven and non-HPV-driven carcinomas and justify the current WHO pathologic classification of PeIN in special subtypes.

Clear Cell Carcinoma of the Penis: An HPV-related Variant of Squamous Cell Carcinoma: A Report of 3 Cases

Penile clear cell carcinoma originating in skin adnexal glands has been previously reported. Here, we present 3 morphologically distinctive penile tumors with prominent clear cell features originating not in the penile skin but in the mucosal tissues of the glans surface squamous epithelium. Clinical and pathologic features were evaluated. Immunohistochemical stains were GATA3 and p16. Human papilloma virus (HPV) detection by in situ hybridization was performed in 3 cases, and whole-tissue section-polymerase chain reaction was performed in 1 case. Patients' ages were 52, 88, and 95 years. Tumors were large and involved the glans and coronal sulcus in all cases. Microscopically, nonkeratinizing clear cells predominated. Growth was in solid nests with comedo-like or geographic necrosis. Focal areas of invasive warty or basaloid carcinomas showing in addition warty or basaloid penile intraepithelial neoplasia were present in 2 cases. There was invasion of corpora cavernosa, lymphatic vessels, veins, and perineural spaces in all cases. p16 was positive, and GATA3 stain was negative in the 3 cases. HPV was detected in 3 cases by in situ hybridization and in 1 case by polymerase chain reaction. Differential diagnoses included other HPV-related penile carcinomas, skin adnexal tumors, and metastatic renal cell carcinoma. Features that support primary penile carcinoma were tumor location, concomitant warty and/or basaloid penile intraepithelial neoplasia, and HPV positivity. Clinical groin metastases were present in all cases, pathologically confirmed in 1. Two patients died from tumor dissemination at 9 and 12 months after penectomy. Clear cell carcinoma, another morphologic variant related to HPV, originates in the penile mucosal surface and is probably related to warty carcinomas.

Human Papillomavirus

Individuals with inherited immunodeficiencies, autoimmune disorders, organ or bone marrow transplantation, or infection with human immunodeficiency virus (HIV) are at increased risk of infection with both low-risk and high-risk human papillomavirus (HPV) types. Chronic immunosuppression provides an environment for persistent HPV infection which carries a higher risk of malignant transformation. Screening guidelines have been developed or advocated for processes that have detectable premalignant lesions, such as anal cancer or cervical cancer. For other anatomic locations, such as cutaneous, penile, and oropharyngeal, a biopsy of suspicious lesions is necessary for diagnosis. HPV cannot be cultured from clinical specimens in the laboratory, and diagnosis relies on cytologic, histologic, or molecular methods.

Genomic Profiling of Penile Squamous Cell Carcinoma Reveals New Opportunities for Targeted Therapy

Penile squamous cell carcinoma (PeSCCA) is a rare malignancy for which there are limited treatment options due to a poor understanding of the molecular alterations underlying disease development and progression. Therefore, we performed comprehensive, targeted next-generation sequencing to identify relevant somatic genomic alterations in a retrospective cohort of 60 fixed tumor samples from 43 PeSCCA cases (including 14 matched primary/metastasis pairs). We identified a median of two relevant somatic mutations and one high-level copy-number alteration per sample (range, 0-5 and 0-6, respectively). Expression of HPV and p16 was detectable in 12% and 28% of patients, respectively. Furthermore, advanced clinical stage, lack of p16 expression, and MYC and CCND1 amplifications were significantly associated with shorter time to progression or PeSCCA-specific survival. Notably, four cases harbored EGFR amplifications and one demonstrated CDK4 amplification, genes for which approved and investigational targeted therapies are available. Importantly, although paired primary tumors and lymph node metastases were largely homogeneous for relevant somatic mutations, we identified heterogeneous EGFR amplification in primary tumor/lymph node metastases in 4 of 14 cases, despite uniform EGFR protein overexpression. Likewise, activating HRAS mutations occurred in 8 of 43 cases. Taken together, we provide the first comprehensive molecular PeSCCA analysis, which offers new insight into potential precision medicine approaches for this disease, including strategies targeting EGFR.

The Emerging Role and Promise of Biomarkers in Penile Cancer

Penile cancer is a rare malignancy, which can be a source of devastating psychosexual distress because of its implication on sexual function and self-image. Current penile staging relies on invasive techniques and is often inaccurate. The authors review the promising biomarkers currently under investigation and their application to the staging and prognosis of penile cancer. Further development of such biomarkers provides the potential of improved clinical management of this disease.

Clinical Significance of p53 and p16(ink4a) Status in a Contemporary North American Penile Carcinoma Cohort

BACKGROUND

Because of the low incidence of penile carcinoma (PC), the value of p16(ink4a), p53, and human papilloma virus (HPV) infection status in clinical practice remains unclear. Herein, we report our experience with potential clinical utility of these markers in men with PC treated at our institution.

PATIENTS AND METHODS

Tissue microarrays of 57 cases of invasive penile squamous cell carcinomas were immunohistochemically stained for p16 and p53. HPV in situ hybridization (ISH) for high-risk subtypes was also performed. Association between marker status, nodal disease, overall (OS) and cancer-specific survival (CSS) were assessed.

RESULTS

p16 and HPV ISH were positive in 23 (40%) and 24 (42%) of the cohort, respectively. The proportion of warty, basaloid, or mixed warty basaloid tumor subtypes were significantly greater in the p16-positive patients (48% vs. 3%; P < .01). p53 expression was negative in 31 (54%) cases. Only in p16-negative patients, positive p53 status was associated with pN+ disease (odds ratio, 4.4 [95% confidence interval (CI), 1.04-18.6]). In Kaplan-Meier analysis, the unadjusted estimated OS was insignificantly longer in p16-positive patients (median OS, 75 vs. 27 months; P = .27) and median CSS was not reached (P = .16). In a multivariable Cox proportional hazard model, when controlling for pathological nodal status and adjuvant chemotherapy, p16 status was a significant predictor for improved CSS (hazard ratio, 0.36 [95% CI, 0.13-0.99]). The worst CSS was seen in pN+ patients with double negative p16 and p53 expression (8 vs. 34 months; P = .01).

CONCLUSION

In this current cohort, p53 and p16 status showed clinical utility in predicting nodal disease as well as survival.

Identification of somatic gene mutations in penile squamous cell carcinoma

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

Grading of atypia in genital skin lesions: routine microscopic evaluation and use of p16 immunostaining

BACKGROUND

p16 immunostaining has been used to aid and improve the histopathologic evaluation of equivocal cervical lesions with associated low-grade or high-grade dysplasia. However, the utility of p16 immunostaining in the diagnosis of atypical genital skin lesions remains debatable.

METHODS

We conducted a cross-sectional study of genital skin lesions with varying degrees of atypia. Four pathologists assessed lesional atypia and interpreted hematoxylin and eosin (H&E) staining and p16 immunostaining without knowledge of original diagnosis. Our primary outcomes were diagnostic agreement and test performance of p16 immunostaining compared to consensus H&E diagnosis.

RESULTS

Our sample was comprised of 23 cases of atypical genital skin lesions. p16 immunostaining was negative in all cases of reactive atypia (n = 3) and the majority (n = 7 of 8; 88%) of low-grade squamous intraepithelial lesions (LSILs). The majority (n = 10 of 12; 83%) of high-grade squamous intraepithelial lesions (HSIL) were p16 positive. Diagnostic agreement for histopathologic assessment using H&E staining was moderate (kappa = 0.44), while inter-observer agreement of p16 immunostaining was excellent (kappa = 0.87). Compared to consensus diagnosis using H&E staining, p16 immunostaining performed well (sensitivity 83.3%; specificity 90.9%).

CONCLUSIONS

p16 immunostaining may be a useful adjunctive marker for assessing dysplasia in genital skin lesions and increasing diagnostic agreement among pathologists.

The role of histologic subtype, p16(INK4a) expression, and presence of human papillomavirus DNA in penile squamous cell carcinoma

Background

Up to 50% of penile squamous cell carcinomas (pSCC) develop in the context of high-risk human papillomavirus (HR-HPV) infection. Most of these tumours have been reported to show basaloid differentiation and overexpression of tumour suppressor protein p16^INK4a. Whether HPV-triggered carcinogenesis in pSCC has an impact on tumour aggressiveness, however, is still subject to research.

Methods

In tissue specimens from 58 patients with surgically treated pSCC between 1995 and 2012, we performed p16^INK4a immunohistochemistry and DNA extraction followed by HPV subtyping using a PCR-based approach. The results were correlated with histopathological and clinical parameters.

Results

90.4% of tumours were of conventional (keratinizing) subtype. HR-HPV DNA was detected in 29.3%, and a variety of p16^INK4a staining patterns was observed in 58.6% of samples regardless of histologic subtype. Sensitivity of basaloid subtype to predict HR-HPV positivity was poor (11.8%). In contrast, sensitivity and specificity of p16^INK4a staining to predict presence of HR-HPV DNA was 100% and 57%, respectively. By focussing on those samples with intense nuclear staining pattern for p16^INK4a, specificity could be improved to 83%. Both expression of p16^INK4a and presence of HR-HPV DNA, but not histologic grade, were inversely associated with pSCC tumour invasion (p = 0.01, p = 0.03, and p = 0.71). However, none of these correlated with nodal involvement or distant metastasis. In contrast to pathological tumour stage, the HR-HPV status, histologic grade, and p16^INK4a positivity failed to predict cancer-specific survival.

Conclusions

Our results confirm intense nuclear positivity for p16^INK4a, rather than histologic subtype, as a good predictor for presence of HR-HPV DNA in pSCC. HR-HPV / p16^INK4a positivity, independent of histological tumour grade, indicates a less aggressive local behaviour; however, its value as an independent prognostic indicator remains to be determined. Since local invasion can be judged without p16^INK4a/HPV-detection on microscopic evaluation, our study argues against routine testing in the setting of pSCC.

Histologic and immunohistochemical assessment of penile carcinomas in a North American population

Penile squamous cell carcinoma (SCC) is sometimes an aggressive disease that has a variable worldwide incidence, in part due to differing rates of inflammatory and infectious risk factors. In the developed world, penile SCC is a rare malignancy, and most studies therefore originate in less developed countries. The current study was undertaken to examine the morphologic and immunohistochemical features of penile SCC from a region with low disease incidence. Sixty-two complete or partial penectomy specimens from 59 patients were reviewed. Twenty-six patients had metastasis, 3 had recurrent disease, and 7 were dead due to tumor. Most patients were uncircumcised (72%). Twenty-two percent of carcinomas were associated with lichen sclerosis. Perineural invasion was significantly associated with metastasis (P=0.007). Most SCCs (65%) had the usual keratinizing morphology, and these tumors were significantly associated with the differentiated form of intraepithelial lesion (P<0.0001), p53 positivity (P=0.002), cyclin D1 positivity (P=0.007), and EGFR overexpression (P=0.003). Human papilloma virus (HPV)-associated tumors accounted for 27% and were basaloid (8%), warty (10%), mixed (6%), or lymphoepithelioma-like carcinoma (4%) variants. These were significantly associated with p16 expression (P<0.0001) and the undifferentiated form of intraepithelial lesion (P<0.001). Among all SCCs, there was no difference in the immunohistochemical or in situ hybridization profile between primary tumors and metastases. Although penile SCC is rare in the United States, the tumor variants, immunohistochemical profiles, and proportion of HPV-associated tumors are similar to those in less developed countries. Two distinct pathways appear to lead to carcinogenesis; one is related to underlying chronic inflammatory states, involves p53 mutation, cyclin D1 overexpression, and culminates in classic keratinizing SCC. The other pathway involves high-risk HPV infection, demonstrates strong p16 expression, and results in SCC with varied, but distinctive morphologies.

mTOR signaling pathway in penile squamous cell carcinoma: pmTOR and peIF4E over expression correlate with aggressive tumor behavior

PURPOSE

Penile squamous cell carcinoma is a rare neoplasm associated with a high risk of metastasis and morbidity. There are limited data on the role of the mTOR signaling pathway in penile squamous cell carcinoma carcinogenesis and tumor maintenance. We assessed a possible role for mTOR signaling pathway activation as a potential predictive biomarker of outcome and a therapeutic target for penile cancer.

MATERIAL AND METHODS

A cohort of 67 patients diagnosed with invasive penile squamous cell carcinoma from 1987 to 2010 who had known HPV status were selected for study. Tissue microarrays were constructed with 67 primary penile squamous cell carcinomas, matched normal tissues and 8 lymph node metastases. Immunohistochemical staining was performed for p53, pmTOR, pERK, p4E-BP1, eIF4E and peIF4E. Expression was evaluated using a semiquantitative H-score on a scale of 0 to 300.

RESULTS

Expression of pmTOR, p4E-BP1, eIF4E and peIF4E was increased in penile tumors compared with matched adjacent normal tissues, indicating activation of the mTOR signaling pathway in penile tumorigenesis. Over expression of pmTOR, peIF4E and p53 was significantly associated with lymph node disease. peIF4E and p53 also correlated with a poor outcome, including recurrence, metastasis or disease specific death. In contrast, pERK and p4E-BP1 were associated with lower pT stages. pmTOR and intense p53 expression was associated with HPV negative tumors.

CONCLUSIONS

Activation of mTOR signaling may contribute to penile squamous cell carcinoma progression and aggressive behavior. Targeting mTOR or its downstream signaling targets, such as peIF4E, may be a valid therapeutic strategy.

Overexpression of ANXA1 in penile carcinomas positive for high-risk HPVs

The incidence of penile cancer varies between populations but is rare in developed nations. Penile cancer is associated with a number of established risk factors and associated diseases including phimosis with chronic inflammation, human papillomavirus (HPV) infection, poor hygiene and smoking. The objective of this study was to identify genes related to this type of cancer. The detection of HPV was analyzed in 47 penile squamous cell carcinoma samples. HPV DNA was detected in 48.9% of penile squamous cell carcinoma cases. High-risk HPV were present in 42.5% of cases and low-risk HPV were detected in 10.6% of penile squamous cell carcinomas. The RaSH approach identified differential expression of Annexin A1 (ANXA1), p16, RPL6, PBEF1 and KIAA1033 in high-risk HPV positive penile carcinoma; ANXA1 and p16 were overexpressed in penile squamous cells positive for high-risk HPVs compared to normal penile samples by qPCR. ANXA1 and p16 proteins were significantly more expressed in the cells from high-risk HPV-positive penile carcinoma as compared to HPV-negative tumors (p<0.0001) independently of the subtype of the carcinoma. Overexpression of ANXA1 might be mediated by HPV E6 in penile squamous cell carcinoma of patients with high-risk HPVs, suggesting that this gene plays an important role in penile cancer.