Merkel cell carcinoma

Exploring the causal role of pathogen-derived antibodies in major urinary and kidney diseases: Insights from generalized summary data-based Mendelian randomization

Chronic kidney and urinary tract diseases, including glomerulonephritis, nephrotic syndrome, and chronic kidney disease (CKD), present significant global health challenges. Recent studies suggest a complex interplay between infectious pathogens and immune-mediated kidney damage. This study employs Generalized Summary data-based Mendelian Randomization (GSMR) to explore causal relationships between pathogen-derived antibodies and major urinary and kidney diseases.We conducted a two-sample MR analysis using summary statistics from large-scale Genome-Wide Association Studies (GWAS) to assess associations between 46 pathogen-specific antibodies and seven urinary system diseases. We utilized robust statistical methods, including inverse variance weighting, to ascertain causal effects while controlling for potential confounders.Significant associations were identified between several pathogen-specific antibodies and disease risk. Notably, Epstein-Barr virus (EBNA-1) antibody levels were inversely associated with glomerulonephritis and nephrotic syndrome, indicating a potential protective effect. Conversely, Anti-Merkel cell polyomavirus IgG seropositivity was linked to increased risks of CKD and glomerulonephritis. Additionally, immune-mediated mechanisms were highlighted, with certain antibodies exhibiting dual roles as risk factors or protective agents.This study underscores the complex role of pathogen antibodies in the pathogenesis of kidney and urinary tract diseases, revealing significant implications for future research and potential therapeutic strategies. The findings advocate for further investigation into specific pathogen interactions with the immune system, aiming to inform targeted interventions.

Functional characterization of the ATOH1 molecular subtype indicates a pro-metastatic role in small cell lung cancer

Molecular subtypes of small cell lung cancer (SCLC) have been described based on differential expression of the transcription factors (TFs) ASCL1, NEUROD1, and POU2F3 and immune-related genes. We previously reported an additional subtype based on expression of the neurogenic TF ATOH1 within our SCLC circulating tumor cell-derived explant (CDX) model biobank. Here, we show that ATOH1 protein is detected in 7 of 81 preclinical models and 16 of 102 clinical samples of SCLC. In CDX models, ATOH1 directly regulates neurogenesis and differentiation programs, consistent with roles in normal tissues. In ex vivo cultures of ATOH1+ CDXs, ATOH1 is required for cell survival. In vivo, ATOH1 depletion slows tumor growth and suppresses liver metastasis. Our data validate ATOH1 as a bona fide lineage-defining TF of SCLC with cell survival and pro-metastatic functions. Further investigation exploring ATOH1-driven vulnerabilities for targeted treatment with predictive biomarkers is warranted.

Surgical Outcomes for Nonmelanoma Skin Cancer of the Head and Neck

OBJECTIVES

There is no consensus on elective lymphatic dissection of the parotid and neck for nonmelanoma skin cancer (NMSC) due to challenges in detecting occult spread to these regions. This study aimed to summarize clinical data and evaluate correlations between risk factors, nodular metastasis, and the need for elective parotidectomy in patients with cutaneous squamous cell carcinoma (CSCC), Merkel cell carcinoma (MCC), and apocrine carcinoma (AC) of the head and neck, all with clear surgical margins and negative imaging results for regional metastases.

STUDY DESIGN

We retrospectively reviewed 166 patients with CSCC, one with MCC, and one with AC of the head and neck, all treated surgically between September 2006 and July 2022. The neck and parotid nodes were imaged preoperatively, and nodular metastases were verified by pathological examination. Age, maximum primary tumor dimension, and primary tumor depth were evaluated in patients with and without nodular metastases.

RESULTS

Seven patients developed nodular metastases after primary tumor excision. Facial paralysis occurred in three of five patients with parotid spread. Age and primary tumor size differed significantly between patients with and without nodular metastases ( P < 0.05). Tumor depth did not differ significantly between these groups ( P > 0.50).

CONCLUSIONS

Negative imaging results of nodular metastases before primary tumor excision and clear margins did not imply exemption from nodular metastases postoperatively. Nodular spread of CSCC is associated with multiple risk factors rather than any single factor. Elective parotidectomy is recommended to prevent facial nerve invasion by occult nodular metastasis in patients with CSCCs with advanced age, large primary tumor size (≥T3), critical tumor locations, and/or pathological types with high metastatic potential.

Merkel cell carcinoma in Taiwan: a subset is chronic arsenicism-related, and the Merkel cell polyomavirus-negative cases are pathologically distinct from virus-related cases with a poorer outcome

Merkel cell carcinoma (MCC) is a rare primary neuroendocrine carcinoma of the skin, more frequent in the West than in the East. The pathogenesis is complex, with Merkel cell polyomavirus (MCPyV) and ultraviolet (UV) light being reported to play important roles. In this retrospective study of MCC cases from Taiwan, we analysed the prognostic significance of pathological features and the status of MCPyV and retinoblastoma (Rb) expression. We retrospectively collected MCC cases from five hospitals in Taiwan from 1994 to 2022. We examined the clinical and pathological features, performed immunohistochemical studies for the large T antigen of MCPyV and Rb, and reviewed medical records from electronic data. Disease-specific survival was estimated by using the Kaplan-Meier estimate and compared between subgroups using log-rank test. The clinical and pathological features and the immunohistochemical profiles between subgroups were compared using the Fisher exact test for categorical variables. The 38 patients were mostly (71%) males, with a median age of 79. In 22 (58%) patients, the tumours occurred in sun-exposed areas. Clinically, five (13%) patients had chronic arsenicism. Histopathologically, 11 (29%) cases showed combined tumours (MCC with squamous cell carcinoma or Bowen disease/squamous carcinoma in situ). Seventeen (45%) cases were positive for MCPyV, whereas all combined tumours were negative. MCPyV-negative MCC displayed distinctive pathological features, including epidermal changes, presence of an intraepidermal MCC component, linear or single-file growth pattern, and pleomorphic nuclei. Immunohistochemically, 59% (22/37) MCC cases showed complete loss of Rb protein expression, more frequent in MCPyV-unrelated (p<0.001) and combined (p=0.014) cases, ​but without statistical significance among patients with chronic arsenicism, sun exposure, or disease-specific survival. MCPyV-negative cases exhibited a shorter disease-specific survival than MCPyV-positive cases (median overall survival 13 months vs not reached; p=0.041). MCPyV-negative or combined MCCs were associated with a higher disease-specific mortality and poorer prognosis. MCCs occurring in sun-shielded sites, MCPyV-negativity, and combined tumours correlated with a higher disease-specific mortality and a poorer prognosis by multivariable Cox proportional hazard model. The occurrence of MCCs with arsenic exposure was also identified. Our study showed that MCPyV-negative MCC cases in Taiwan exhibited distinctive pathological features and a poorer outcome than MCPyV-related cases. We also confirmed an association of chronic arsenicism with MCC, which might be considered as the third pathogenetic factor after MCPyV and UV light. Further studies including epidemiological and genetic investigations are warranted to elucidate the pathogenesis of MCC in Taiwan, particularly the significance of chronic arsenicism.

Treatment of Merkel cell carcinoma in organ transplant recipients-A systematic review

Background

There are no clear treatment guidelines for solid organ transplantation (SOT) patients with Merkel cell carcinoma (MCC) despite increased incidence rates.

Objective

To review treatment outcomes of MCC patients with prior SOT.

Methods

A systematic review (Prospective Register of Systematic Reviews CRD42024569200) of studies that reported treatment modalities and outcomes for MCC patients with SOT were selected. Databases screened included PubMed, Web of Science, Scopus, and Embase.

Results

Thirty articles comprising 21 case reports, 8 cohort studies, and 1 clinical trial were included. Treatment modalities reported in case reports and clinical trials included surgery (77.7%), radiotherapy (62.9%), and chemotherapy (25.9%), with 3 patients receiving immune checkpoint inhibitors and 1 patient receiving an oncolytic virus. Cohort studies reported varying usage of surgery, radiotherapy, chemotherapy, and immunosuppression regime modifications.

Limitations

Heterogeneity in methodologies and data reporting of studies included impeded meaningful comparisons. Lack of stratification of immunosuppressed populations in the excluded studies reduced the available patient data for comparison.

Conclusion

Oncolytic virotherapy has the potential to mediate a localized, targeted response with minimal side effects in SOT patients. Inclusion of SOT patients with MCC into future clinical trials involving immunotherapy and immunosuppression combination therapies is needed to establish future treatment guidelines.

Advances in Skin Ultrasonography for Malignant and Benign Tumors of the Head and Neck: Current Insights and Future Directions

Ultrasound imaging has become an indispensable diagnostic tool across various medical fields. In recent years, there has been growing interest in the use of ultrasonography for the evaluation of skin lesions. However, scientific reports detailing the precise role of ultrasound in determining the morphology of malignant skin tumors still remain limited. Malignant skin lesions, particularly in the head and neck region-their most common location-pose significant challenges due to the complex anatomy of these areas. The primary treatment for non-melanoma skin cancers, including basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), is surgical excision. Mohs micrographic surgery is considered the gold standard due to its tissue-sparing approach and high cure rates. However, it is a time-consuming and resource-intensive procedure that is not always widely accessible. In contrast, standard surgical excision, while more widely available, often results in incomplete tumor removal, necessitating subsequent surgical radicalization or the use of adjuvant therapies. Routine ultrasound evaluation of both benign and malignant skin lesions could enhance early detection and facilitate timely treatment. However, the current body of evidence for the usage of skin ultrasound in presurgical evaluation is poor and lacks standardization. Given these challenges, in this review, we aim to highlight the potential value of preoperative skin ultrasonography in accurately assessing benign and malignant skin lesion dimensions and morphology.

Overview of skin cancer types and prevalence rates across continents

Skin cancer is one of the most prevalent cancers in the world, and its incidence and mortality rates are increasing continuously, mostly in regions with white-skinned inhabitants. The types of skin cancer vary in their origin and clinical appearances and also differ in their extensiveness. The continents of the world have different scenarios of skin cancer prevalence. This review aims to explore the different types of skin cancer, their clinical features, and their worldwide prevalence based on the literature. Literature from different electronic databases, including Google Scholar, ResearchGate, PubMed, Scopus, Web of Science, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Elsevier, and Springer, were collected through a literature search using specific keywords such as "skin cancer", "skin cancer types", "melanoma", "non-melanoma", "skin cancer continental prevalence" or similar keywords. The search included English publications from 2000 to 2024. Melanoma skin cancer (MSC) ranks 17th in global prevalence, with the highest incidence and deaths occurring in Europe, However, Australia and New Zealand record the highest incidence and mortality rates. Asia has a lower incidence rate of melanoma, but a higher mortality rate. Superficial spreading melanoma (SSM) is the most common type of MSC. Non-melanoma skin cancers (NMSCs) have the highest incidence in North America, with the highest number of deaths occurring in Asia, Australia and New Zealand have the highest incidence rates for basal cell carcinoma (BCC). BCC is the most commonly diagnosed skin cancer worldwide and the most prevalent form of NMSCs; however, squamous cell carcinoma is the most aggressive form of NMSCs, causing more deaths. NMSCs are the most prevalent cancers worldwide, causing most skin cancer-related deaths. The prevalence of skin cancer rising globally, with several continents experiencing higher incidence and mortality rates. The types and subtypes of skin cancer are becoming more common among clinically diagnosed cancers. This review comprehensively describes skin cancer types and their prevalence worldwide. However, the actual prevalence of skin cancer in these countries should be investigated. Further research on the prevalence of skin cancer across different continents is required to develop more effective cancer management strategies and control the spread of the disease.

Importance of Surgical Margins in Patients with Early-Stage Merkel Cell Carcinoma

INTRODUCTION

The National Comprehensive Cancer Network (NCCN) recommends excision of the primary tumor using 1-2-cm surgical margins and sentinel lymph node biopsy (SLNB) as the initial management of early-stage Merkel cell carcinoma (MCC). However, there is no clear consensus on the appropriate size of the surgical margins and/or the use of Mohs micrographic surgery (MMS). Our aim was to demonstrate that, independent of the type of surgery, obtaining negative surgical margins is associated with enhanced overall survival (OS).

METHODS

A retrospective study was performed using early-stage MCC patients from the National Cancer Database (NCDB) who were diagnosed between 2004 and 2020 and underwent surgical excision (SE) of their primary tumor. Patients were stratified into three groups based on the surgical treatment they received: < 1 cm excision margin, ≥ 1 cm excision margin, or MMS. OS was assessed with Kaplan-Meier curves, log-rank tests, and multivariable risk-adjusted Cox proportional-hazards regression.

RESULTS

Of the 4,607 patients included in this study; 53% underwent SE of ≥ 1 cm (n = 2,474), 41% had SE < 1 cm (n = 1,905), and the remainder had MMS (n = 228). 75% of patients had an SLNB, and 56% received adjuvant radiation to the primary site and/or nodal basin. While no difference in OS was observed between the three surgical treatments, negative surgical margins (hazard ratio (HR) 0.78; 95% confidence interval (CI) 0.65-0.94) and receipt of radiation to the primary site (HR 0.82; 95% CI 0.73-0.92) were both independently associated with improved OS.

CONCLUSION

Achieving negative surgical margins is associated with improved OS in MCC, suggesting that MMS and conventional excision are both suitable approaches for the treatment of primary MCC.

Low Intratumoral CD200 Protein Expression in Primary Merkel Cell Carcinoma Is a Strong Predictor for Disease Relapse

BACKGROUND

Merkel cell carcinoma (MCC) is a rare and frequently fatal form of skin cancer. Apart from Programmed Cell Death Protein 1 (PD-1)/Programmed Death-Ligand 1 (PD-L1) signaling, there is a lack of knowledge regarding other immune checkpoint molecules. Recent studies have observed elevated glycoprotein CD200 (also known as OX-2) mRNA expression in in different types of tumors, with CD200R-expressing myeloid cells present in the tumor microenvironment. However, the potential role of the CD200/CD200 axis as an additional checkpoint modulator remains widely unexplored. The aim of this study was to determine the intratumoral protein expression of CD200 as well as CD200R in a larger cohort of MCC patients and to correlate the expression levels with patients' outcomes.

METHODS

In this multicenter study, we investigated 68 patients with MCC (68 primary tumors and 15 corresponding metastases). Immunohistochemistry (IHC) was performed for CD200 as well as CD200R. Digital quantification and analysis of IHC were performed using QuPath-0.2.3.

RESULTS

CD200 and CD200R expression was observed in 100% of cases. Univariate analysis revealed that low CD200 expression in primary tumors (p = 0.0007, HR 9.35), male sex (p = 0.045, HR 2.41), and immunosuppression (p = 0.0031, HR 6.36) were significantly associated with MCC relapse. Low CD200 expression was also linked to prior immune checkpoint inhibitors (ICI) and/or chemotherapy treatment (p = 0.037). Multivariable analysis confirmed that low CD200 expression (p = 0.0012, HR 5.25) and immunosuppression (p = 0.0056, HR 4.11) were independent predictors of MCC relapse.

CONCLUSIONS

Expression of CD200/CD200R proteins is very high in MCC and may thus be of diagnostic value. More importantly, low intratumoral CD200 protein expression in primary MCC represents a robust independent predictor of MCC relapse.

Integrative analysis reveals therapeutic potential of pyrvinium pamoate in Merkel cell carcinoma

Merkel Cell Carcinoma (MCC) is an aggressive neuroendocrine cutaneous malignancy arising from either ultraviolet-induced mutagenesis or Merkel cell polyomavirus (MCPyV) integration. Despite extensive research, our understanding of the molecular mechanisms driving the transition from normal cells to MCC remains limited. To address this knowledge gap, we assessed the impact of inducible MCPyV T antigens on normal human fibroblasts by performing RNA-seq. Our data uncovered changes in expression and regulation of Wnt signaling pathway members. Building on this observation, we bioinformatically evaluated various Wnt pathway perturbagens for their ability to reverse the MCC gene expression signature and identified pyrvinium pamoate, an FDA-approved anthelminthic drug known for its antitumor activity in other cancers. Leveraging transcriptomic, network, and molecular analyses, we found that pyrvinium targets multiple MCC vulnerabilities. Pyrvinium not only reverses the neuroendocrine features of MCC by modulating canonical and noncanonical Wnt signaling but also inhibits cancer cell growth by activating p53-mediated apoptosis, disrupting mitochondrial function, and inducing endoplasmic reticulum stress. Finally, we demonstrated that pyrvinium reduces tumor growth in an MCC mouse xenograft model. These findings offer a deeper understanding of the role of Wnt signaling in MCC and highlight the utility of pyrvinium as a potential treatment for MCC.

Sustained Release of HIF-2α Inhibitors Using Biodegradable Porous Silicon Carriers for Enhanced Immunogenic Cell Death of Malignant Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a rare but aggressive neuroendocrine skin cancer with limited treatment options, often associated with Merkel cell polyomavirus (MCPyV) and marked by hypoxic tumor microenvironments that promote resistance to therapies. Belzutifan, an FDA-approved hypoxia-inducible factor-2α (HIF-2α) inhibitor, has shown promise in inhibiting tumor growth; however, its clinical efficacy is hindered by its low solubility, rapid clearance, and limited bioavailability. In this study, we present a strategy using porous silicon (pSi) microparticles and nanoparticles as carriers for the sustained delivery of benzoate to MCC cells. The pSi carriers were engineered to securely encapsulate and gradually release belzutifan, overcoming the limitations of free drug administration. Microparticles provided sustained extracellular release, while nanoparticles enabled efficient intracellular delivery, enhancing HIF-2α inhibition. Moreover, the use of biodegradable silicon particles enables long-term consistent release of belzutifan over 10 days in vitro with a single dose administration in the tumor microenvironment, while free belzutifan is rapidly deactivated within 1 day postadministration. In vitro studies demonstrated significant immunogenic cell death (ICD) in MCC cells, marked by the cytosolic localization of HMGB1 and elevated expression of pro-inflammatory cytokines as well as strong upregulation of TLR9. Particularly, the increased TLR9 expression in both MCC cell lines with pSi carrier treatment reinforces immune activation through toll-like receptor signaling, enhancing both innate and adaptive immune responses within the tumor microenvironment. These findings indicate that pSi carriers not only enhance belzutifan's stability and release profile but also amplify antitumor immune responses within the tumor microenvironment. Our results suggest that belzutifan-loaded pSi carriers offer a potent and targeted therapeutic strategy for MCC, potentially addressing key challenges in cancer immunotherapy by combining HIF-2α inhibition with robust immune activation. This platform highlights the universal utility of pSi-based delivery systems to advance MCC treatment with implications for broader cancer therapies.

A hybrid machine learning approach for the personalized prognostication of aggressive skin cancers

Accurate prognostication guides optimal clinical management in skin cancer. Merkel cell carcinoma (MCC) is the most aggressive form of skin cancer that often presents in advanced stages and is associated with poor survival rates. There are no personalized prognostic tools in use in MCC. We employed explainability analysis to reveal new insights into mortality risk factors for this highly aggressive cancer. We then combined deep learning feature selection with a modified XGBoost framework, to develop a web-based prognostic tool for MCC termed 'DeepMerkel'. DeepMerkel can make accurate personalised, time-dependent survival predictions for MCC from readily available clinical information. It demonstrated generalizability through high predictive performance in an international clinical cohort, out-performing current population-based prognostic staging systems. MCC and DeepMerkel provide the exemplar model of personalised machine learning prognostic tools in aggressive skin cancers.

A Comparative Study of Merkel Cell Carcinoma and Melanoma Incidence and Survival in the United States, 2000-2021

Merkel cell carcinoma (MCC) and melanoma are important contributors to skin cancer mortality in the United States. We evaluated their epidemiology using the United States cancer registry data. In 2000-2021, 19,444 MCCs and 646,619 melanomas of the skin were diagnosed. Ninety percent of MCCs and 95% of melanomas were in non-Hispanic White individuals. More than 70% of MCCs versus 37% of melanomas occurred in people aged ≥70 years. Excess MCCs and melanomas were observed on the head and neck (observed:expected: MCC, 5.15; melanoma, 2.47). Among non-Hispanic White individuals, ambient UVR exposure was associated with melanoma arising on the head and neck (incidence rate ratios of 1.15-1.20 for MCC and 1.24-1.49 for melanoma, comparing quintiles 3-5 with quintile 1). Cancer-specific mortality was higher among patients with MCC than among those with melanoma (hazard ratio = 2.33, 95% confidence interval = 2.26-2.42) but improved in both groups after 2011 when BRAF and checkpoint inhibitors were introduced. In conclusion, melanoma exhibited stronger associations with race and ambient UVR exposure, while MCC was more likely to arise on the head and neck (perhaps reflecting the distribution of precursor cells). To ensure prompt treatment, clinicians should be on alert when diagnosing these cancers.

Avelumab to treat Merkel cell carcinoma: real-life experience in a dedicated oncology center

The arrival of immunotherapy has revolutioned the management of patients with metastatic Merkel cell carcinoma (MCC). We conducted an observational, retrospective study of 14 cases treated with avelumab. The response rate was 57%: complete response was reached in 29% of patients, and partial responses in 29%. The drug proved effective in 83% (5/6) of the patients with a single metastatic site. However, the disease progressed in 75% (3/4) of the patients with bone metastases. PD1-L expression, MCC polyomavirus (MCPyV) positivity, and an impaired neutrophil-to-lypmhocyte ratio (NLR) could not be associated with responses to the therapy. Avelumab is an effective and safe drug for the management of advanced MCC, and its effectiveness appears to be impacted by the number and location of metastases.

Merkel Cell Carcinoma and Immunosuppression, UV Radiation, and Merkel Cell Polyomavirus

Importance

Merkel cell carcinoma (MCC) is a rare but aggressive skin cancer. Quantifying the contribution of major potentially modifiable risk factors to the burden of MCC may inform prevention efforts.

Objective

To estimate the population attributable fraction of MCC cases in the US that were attributable to major immunosuppressing conditions (eg, HIV, solid organ transplant, chronic lymphocytic leukemia [CLL]), ambient UV radiation [UVR] exposure, and Merkel cell polyomavirus [MCPyV]).

Design, Setting, and Participants

This epidemiological assessment combined data from population-based registries and case series and included cases of MCC that were diagnosed from January 2001 to December 2019 diagnosed in people with HIV, solid organ transplant recipients, and patients with CLL who were identified through population-based cancer registries and linkages with HIV and transplant registries. UVR-based on cloud-adjusted daily ambient UVR irradiance was merged with cancer registry data on the county of residence at diagnosis. Studies reporting the prevalence of MCPyV in MCC specimens collected in the US were combined via a meta-analysis.

Exposures

HIV, solid organ transplant, CLL, UVR, and MCPyV.

Main Outcomes and Measures

Population attributable fraction of MCC cases attributable to major risk factors.

Results

A total of 38 020 MCCs were diagnosed in the US among xx patients (14 325 [38%] female individuals; 1586 [4%] Hispanic, 561 [1%] non-Hispanic Black, and 35 171 [93%] non-Hispanic White individuals). Compared with the general US population, MCC incidence was elevated among people with HIV (standardized incidence ratio [SIR], 2.78), organ transplant recipients (SIR, 13.1), and patients with CLL (SIR, 5.75). Due to the rarity of these conditions, only 0.2% (95% CI, 0.1%-0.3%) of MCC cases were attributable to HIV, 1.5% (95% CI, 1.4%-1.7%) to solid organ transplant, and 0.8% (95% CI, 0.5%-1.3%) to CLL. Compared with individuals of racial and ethnic minority groups, MCC incidence was elevated among non-Hispanic White individuals at lower and higher ambient UVR exposure levels (incidence rate ratios: 4.05 and 4.91, respectively, for MCC on the head and neck). Overall, 65.1% (95% CI, 63.6%-66.7%) of MCCs were attributable to UVR. Based on a meta-analysis of 19 case series, 63.8% (95% CI, 54.5%-70.9%) of MCCs were attributable to MCPyV. Studies were identified from a MEDLINE search performed on October 12, 2023.

Conclusions and Relevance

The results of this study suggest that most MCC cases in the US were attributable to ambient UVR exposure or MCPyV, with a small fraction due to immunosuppressive conditions. Efforts to lower MCC incidence could focus on limiting UVR exposure.

Integrative analysis reveals therapeutic potential of pyrvinium pamoate in Merkel cell carcinoma

Merkel Cell Carcinoma (MCC) is an aggressive neuroendocrine cutaneous malignancy arising from either ultraviolet-induced mutagenesis or Merkel cell polyomavirus (MCPyV) integration. Despite extensive research, our understanding of the molecular mechanisms driving the transition from normal cells to MCC remains limited. To address this knowledge gap, we assessed the impact of inducible MCPyV T antigens on normal human fibroblasts by performing RNA sequencing. Our data uncovered changes in expression and regulation of Wnt signaling pathway members. Building on this observation, we bioinformatically evaluated various Wnt pathway perturbagens for their ability to reverse the MCC gene expression signature and identified pyrvinium pamoate, an FDA-approved anthelminthic drug known for its anti-tumor activity in other cancers. Leveraging transcriptomic, network, and molecular analyses, we found that pyrvinium targets multiple MCC vulnerabilities. Pyrvinium not only reverses the neuroendocrine features of MCC by modulating canonical and non-canonical Wnt signaling but also inhibits cancer cell growth by activating p53-mediated apoptosis, disrupting mitochondrial function, and inducing endoplasmic reticulum stress. Finally, we demonstrated that pyrvinium reduces tumor growth in an MCC mouse xenograft model. These findings offer a new understanding of the role of Wnt signaling in MCC and highlight the utility of pyrvinium as a potential treatment for MCC.

Changes in Merkel cell oncoprotein antibodies after radiation therapy in curatively treated Merkel cell carcinoma and association with recurrence

BACKGROUND

Serum antibodies to the Merkel oncoprotein (AMERK) are detectable in approximately 50% of patients with Merkel cell carcinoma (MCC) and can be used to monitor for recurrence. The objective of this study was to characterize AMERK levels in patients receiving curative-intent radiation therapy (RT) for MCC and identify associations between AMERK and recurrence.

METHODS

This was a retrospective study of patients with MCC who had baseline AMERK measurements before they received curative-intent RT from 2010 to 2020. Event-free survival (EFS) was calculated using the Kaplan-Meier method and Cox regression. The cumulative incidence of MCC-related recurrence (CIMR) was analyzed with death as a competing risk and the Gray test.

RESULTS

The authors identified 88 patients who had baseline AMERK measurements, including 52 (59%) with detectable levels. AMERK positivity was associated with younger median age (67.8 vs. 72.0 years; p = .02) and tumor site (p = 0.02), with lower rates for those who had disease in the head/neck region (17.3% vs. 44.4%). EFS (71.3% vs. 60.4%; p = .30) and CIMR (24.4% vs. 39.6%; p = .23) were more favorable in AMERK-positive patients. Two patients had recurrences in the RT field, and both were AMERK-negative at baseline. The median time to AMERK nadir after RT was 11.2 months; and, in a 6-month post-RT landmark analysis, the proportion of patients who were AMERK-positive who became negative or who had levels that decreased by ≥50% were not associated with EFS (87.1% vs. 85.0%; p = .90) or CIMR (12.9% vs. 15.0%; p = .62).

CONCLUSIONS

Positive AMERK baseline levels were correlated with younger age at MCC diagnosis and nonhead and neck tumor location, possibly related to the distribution of viral etiology. A specific post-RT AMERK decline correlating with EFS could not be identified.

Re-exposition to ipilimumab plus nivolumab in metastatic Merkel cell carcinoma

Background

Merkel cell carcinoma (MCC) is a rare but highly aggressive cutaneous malignancy. Immune checkpoint inhibition (ICI) with PD-(L)1 blockade has significantly improved treatment outcomes in metastatic disease. In patients with primary resistance to PD-(L)1 inhibition, a high overall response rate (ORR) of 50% to later-line ipilimumab plus nivolumab (IPI/NIVO) has been demonstrated. However, clinical data on patients with progression after an initial response to IPI/NIVO are still lacking.

Methods

Clinical data of three metastatic MCC patients who were re-exposed to IPI/NIVO after progression were retrospectively evaluated.

Results

Two of the three patients showed primary resistance to avelumab with progressive disease, while one patient showed complete response (according to RECIST V.1.1). All three patients received combined ICI with IPI/NIVO as subsequent therapy, resulting in an ORR of ∼ 67%. However, all three patients progressed during follow-up and were re-exposed to IPI/NIVO. With a follow-up period ranging from 6.5 to 37.1 months, no PFS event has been detected. ORR for IPI/NIVO re-exposition was equal to that of initial IPI/NIVO treatment.

Conclusion

In this retrospective follow-up analysis, we observed a response rate of 67% and long-lasting responses after re-exposition to combined ICI in metastatic MCC patients with progression after initial response or disease control upon their first IPI/NIVO treatment. An important observation from this small analysis is that primary resistance to PD-L1 inhibition may result in a better response to IPI/NIVO.

Incidence and outcomes of Merkel cell carcinoma related to Merkel cell polyomavirus status in Iceland in 1981-2023

Background

Impact of Merkel cell polyomavirus (MCPyV) associated Merkel cell carcinoma (MCC) has not been assessed in the Icelandic population, nor in a whole population elsewhere.

Objectives

The primary objective was to assess trends in the incidence of MCC in Iceland and the association with MCPyV. Secondary objectives aimed to analyze MCC outcomes.

Methods

In this retrospective cohort study, patients diagnosed with MCC between 1981 and 2021 were identified from the Icelandic Cancer Registry. Patients were separated into 2 groups based on MCPyV immunochemistry staining. Age-standardized incidence was calculated and Joinpoint analysis was used to assess incidence trends. A Cox proportional hazards model was used to assess survival differences between the 2 groups.

Results

Overall incidence of MCC increased from 0.015 to 0.26 per 100,000 persons, though the incidence of MCPyV positive cases recently decreased while negative cases increased. MCPyV negative tumors were associated with sun exposure (P < .01), a history of keratinocyte carcinoma, smaller tumor size, and lower overall survival.

Limitations

Even with population-level data, comprehensively investigating associations with MCC is difficult due to its rarity.

Conclusion

MCPyV negative MCC tumors were associated with lower survival despite smaller tumor size. Thus, MCPyV status could be an important prognostic biomarker.

Rare Case of Germline GATA2-Deficiency With Merkel Cell Carcinoma and Acute Myeloid Leukemia

BACKGROUND

Germline GATA2-deficiency usually manifests as immunodeficiencies and myeloid neoplasms and sometimes with dermatological diseases, including warts, panniculitis, and skin cancers.

CASE

We report a 36-year-old woman with germline GATA2-deficiency who developed Merkel cell carcinoma followed by acute myeloid leukemia. Molecular analysis revealed a germline GATA2 S447R variant, not reported from the previous reported case, suggesting a potential association with Merkel cell carcinoma.

CONCLUSION

This case broadens the spectrum of solid cancers linked to GATA2-deficiency, emphasizing the need for considering primary immunodeficiency in young patients with myeloid neoplasms or rare skin cancers, facilitating early detection and treatments.

Unraveling the landscape of non-melanoma skin cancer through single-cell RNA sequencing technology

Non-melanoma skin cancer (NMSC) mainly includes basal cell carcinoma, cutaneous squamous cell carcinoma, and Merkel cell carcinoma, showing a low mortality rate but the highest incidence worldwide. In recent decades, research has focused on understanding the pathogenesis and clinical treatments of NMSC, leading to significant advances in our knowledge of these diseases and the development of novel therapies, including immunotherapy. Nevertheless, the low to moderate objective response rate, high recurrence, and therapeutic resistance remain persistent challenges, which are partly attributable to the intratumoral heterogeneity. This heterogeneity indicates that tumor cells, immune cells, and stromal cells in the tumor microenvironment can be reshaped to a series of phenotypic and transcriptional cell states that vary in invasiveness and treatment responsiveness. The advent of single-cell RNA sequencing (scRNA-seq) has enabled the comprehensive profiling of gene expression heterogeneity at the single-cell level, which has been applied to NMSC to quantify cell compositions, define states, understand tumor evolution, and discern drug resistance. In this review, we highlight the key findings, with a focus on intratumoral heterogeneity and the mechanism of drug resistance in NMSC, as revealed by scRNA-seq. Furthermore, we propose potential avenues for future research in NMSC using scRNA-seq.

Different prognosis in cutaneous early-onset and late-onset Merkel cell carcinoma: a population-based retrospective study

BACKGROUND

Merkel cell carcinoma (MCC) is a rare and highly aggressive form of skin cancer. However, there is limited research on the clinicopathological features of early-onset MCC (EOMCC) and the differences between EOMCC and late-onset MCC (LOMCC). Our objective was to evaluate the clinicopathological features and cancer-specific survival (CSS) of EOMCC.

METHODS

Our cohort study analyzed data from the Surveillance, Epidemiology, and End Results (SEER) database from January 1, 2018, to December 31, 2020. Data from 1941 patients who were diagnosed with primary cutaneous MCC were included. We then divided the patients with MCC into two groups: those with EOMCC (526 patients) and those with LOMCC (1415 patients). CSS is used as the primary outcome.

RESULTS

The EOMCC group exhibited trends toward advanced tumor progression, an expanded surgical scope, increased lymph node retrieval, intensified radiotherapy, greater utilization of systemic therapy, and a better prognosis. Multivariate analysis revealed that LOMCC (HR 3.305 [2.002-5.456], P < 0.001), advanced T stage (HR 1.430 [1.139-1.797], P = 0.002), advanced N stage (HR 1.522 [1.221-1.897], P < 0.001), M1 stage (HR 2.587 [1.480-4.521], P < 0.001), and radiation (HR 0.586 [0.410-0.837], P = 0.003) were significantly associated with CSS. Among these factors, EOMCC/LOMCC was most strongly associated with CSS, indicating that LOMCC is an independent risk factor for CSS. Interestingly, we found that regional EOMCC and localized or in situ LOMCC had almost completely overlapping survival curves (Plog-rank = 0.620). Additionally, we observed that the TNM staging + age model was a more accurate predictor of CSS among MCC patients than using TNM staging alone.

CONCLUSIONS

We found that EOMCC has distinct clinicopathological features compared to LOMCC. EOMCC is associated with better CSS. The combination of TNM staging and age was more accurate for predicting patient outcomes than TNM staging alone.

War or peace: Viruses and metastasis

Metastasis, the dissemination of malignant cells from a primary tumor to secondary sites, poses a catastrophic burden to cancer treatment and is the predominant cause of mortality in cancer patients. Metastasis as one of the main aspects of cancer progression could be strongly under the influence of viral infections. In fact, viruses have been central to modern cancer research and are associated with a great number of cancer cases. Viral-encoded elements are involved in modulating essential pathways or specific targets that are implicated in different stages of metastasis. Considering the continuous emergence of new viruses and the establishment of their contribution to cancer progression, the warfare between viruses and cancer appears to be endless. Here we aimed to review the critical mechanism and pathways involved in cancer metastasis and the influence of viral machinery and various routes that viruses adopt to manipulate those pathways for their benefit.

Wnt/β-Catenin-Activated Nonpilomatrical Carcinoma of the Skin: A Case Series

Among skin epithelial tumors, recurrent mutations in the APC/CTNNB1 genes resulting in activation of the Wnt/β-catenin pathway have been reported predominantly in neoplasms with matrical differentiation. In the present study, we describe the morphologic, immunohistochemical, and genetic features of 16 primary cutaneous carcinomas harboring mutations activating the Wnt/β-catenin pathway without evidence of matrical differentiation, as well as 4 combined tumors in which a similar Wnt/β-catenin-activated carcinoma component was associated with Merkel cell carcinoma (MCC) or pilomatrical carcinoma. Among the pure tumor cases, 6 of 16 patients were women with a median age of 80 years (range, 58-98 years). Tumors were located on the head and neck (n = 7, 44%), upper limb (n = 4, 25%), trunk (n = 3, 18%), and leg (n = 2, 13%). Metastatic spread was observed in 4 cases resulting in death from disease in 1 patient. Microscopically, all cases were poorly differentiated neoplasms infiltrating the dermis and/or subcutaneous tissue. In 13 cases, solid "squamoid" areas were associated with a basophilic component characterized by rosette/pseudoglandular formation resulting in a biphasic appearance. Three specimens consisted only of poorly differentiated carcinoma lacking rosette formation. Immunohistochemical studies showed frequent expression of EMA (100%), BerEP4 (100%), cytokeratin 7 (94%), chromogranin A (44%), synaptophysin (82%), and cytokeratin 20 (69%). Complete loss of Rb expression was observed in all but 1 case. Nuclear β-catenin and CDX2 expressions were detected in all cases. Recurrent pathogenic somatic mutations were observed in APC (60%), CTNNB1 (40%), and RB1 (n = 47%). Global methylation analysis confirmed that cases with rosette formation constituted a homogeneous tumor group distinct from established skin tumor entities (pilomatrical carcinoma, MCC, and squamous cell carcinoma), although the 3 other cases lacking such morphologic features did not. In addition, we identified 4 combined neoplasms in which there was a component showing a similar poorly differentiated rosette-forming carcinoma demonstrating Rb loss and β-catenin activation associated with either MCC (n = 3) or pilomatrical carcinoma (n = 1). In conclusion, we describe a distinctive neoplasm, for which we propose the term "Wnt/β-catenin-activated rosette-forming carcinoma," morphologically characterized by the association of rosette formation, squamous and/or neuroendocrine differentiation, diffuse CDX2 expression, Rb loss, and mutations in CTNNB1/APC genes.

Facial Merkel cell carcinoma in a 92-year-old man: A case report

Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer that can be easily misdiagnosed in its early stages. Clinicians should maintain a high index of suspicion for rapidly growing skin lesions in elderly patients and promptly investigate with histopathology and immunohistochemistry. Treatment for MCC should be individualized, considering the patient's age, overall health, and quality of life. Close follow-up is essential to detect recurrence or metastasis early.

Rare hepatic metastasis of Merkel cell carcinoma masquerading as hepatocellular carcinoma

A 52-year-old male was diagnosed with primary liver cancer in June 2021 after experiencing abdominal pain and bloating. He had previously undergone resection for a Merkel cell tumor in March 2021, with no metastasis found. Three months later, imaging suggested a liver mass consistent with liver cancer. Lab tests showed elevated hepatitis B surface antigen (>130 IU/ml) and alpha-fetoprotein (24.54 IU/ml), and the imaging features resembled hepatocellular carcinoma (HCC).Finally,it was diagnosed as liver metastasis of Merkel cell carcinoma by pathology.

A Review of Non-Invasive Skin Imaging in Merkel Cell Carcinoma: Diagnostic Utility and Clinical Implications

Background/Objectives: Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous neuroendocrine malignancy characterized by its propensity for rapid growth and early regional and distant metastasis. Given its potentially lethal nature, accurate and timely diagnosis of MCC is of utmost importance. This review aims to describe non-invasive imaging methods that can serve as additional tools in the examination of MCC. Methods: In this narrative review, we describe the up-to-date spectrum of non-invasive skin-imaging methods that can serve as additional tools in the examination of MCC based on the available literature. Dermoscopy might enhance the clinical diagnosis of MCC, facilitate differentiation from other benign and malignant tumors, and help optimize the treatment plan. New imaging technologies might also provide useful information at a sub-macroscopic level and support clinical diagnosis. These techniques include high-frequency ultrasound (HFUS), reflectance confocal microscopy (RCM) and optical coherence tomography (OCT). Results: Clinically, MCC typically presents as a rapidly growing, red, purple or skin-colored painless and firm nodule. Diagnosis is usually established with histopathological assessment and immunohistochemistry. However, dermoscopy and new imaging technologies might enhance the clinical diagnosis of MCC, facilitate differentiation from other benign and malignant tumors, and help optimize the treatment plan.

Ultraviolet (UV) radiation: a double-edged sword in cancer development and therapy

It has long been widely acknowledged that ultraviolet (UV) light is an environment risk factor that can lead to cancer, particularly skin cancer. However, it is worth noting that UV radiation holds potential for cancer treatment as a relatively high-energy electromagnetic wave. With the help of nanomaterials, the role of UV radiation has caught increasing attention in cancer treatment. In this review, we briefly summarized types of UV-induced cancers, including malignant melanoma, squamous cell carcinoma, basal cell carcinoma, Merkel cell carcinoma. Importantly, we discussed the primary mechanisms underlying UV carcinogenesis, including mutations by DNA damage, immunosuppression, inflammation and epigenetic alterations. Historically limited by its shallow penetration depth, the introduction of nanomaterials has dramatically transformed the utilization of UV light in cancer treatment. The direct effect of UV light itself generally leads to the suppression of cancer cell growth and the initiation of apoptosis and ferroptosis. It can also be utilized to activate photosensitizers for reactive oxygen species (ROS) production, sensitize radiotherapy and achieve controlled drug release. Finally, we comprehensively weigh the significant risks and limitations associated with the therapeutic use of UV radiation. And the contradictory effect of UV exposure in promoting and inhibiting tumor has been discussed. This review provides clues for potential clinical therapy as well as future study directions in the UV radiation field. The precise delivery and control of UV light or nanomaterials and the wavelength as well as dose effects of UV light are needed for a thorough understanding of UV radiation.

Targeted Drug Delivery in Periorbital Non-Melanocytic Skin Malignancies

Targeted drug delivery has emerged as a transformative approach in the treatment of periorbital skin malignancies, offering the potential for enhanced efficacy and reduced side effects compared to traditional therapies. This review provides a comprehensive overview of targeted therapies in the context of periorbital malignancies, including basal cell carcinoma, squamous cell carcinoma, sebaceous gland carcinoma, and Merkel cell carcinoma. It explores the mechanisms of action for various targeted therapies, such as monoclonal antibodies, small molecule inhibitors, and immunotherapies, and their applications in treating these malignancies. Additionally, this review addresses the management of ocular and periocular side effects associated with these therapies, emphasizing the importance of a multidisciplinary approach to minimize impact and ensure patient adherence. By integrating current findings and discussing emerging trends, this review aims to highlight the advancements in targeted drug delivery and its potential to improve treatment outcomes and quality of life for patients with periorbital skin malignancies.

[Translated article] Avelumab to treat Merkel cell carcinoma: real-life experience in a dedicated oncology center

The arrival of immunotherapy has revolutioned the management of patients with metastatic Merkel cell carcinoma (MCC). We conducted an observational, retrospective study of 14 cases treated with avelumab. The response rate was 57%: complete response was reached in 29% of patients, and partial responses in 29%. The drug proved effective in 83% (5/6) of the patients with a single metastatic site. However, the disease progressed in 75% (3/4) of the patients with bone metastases. PD1-L expression, MCC polyomavirus (MCPyV) positivity, and an impaired neutrophil-to-lypmhocyte ratio (NLR) could not be associated with responses to the therapy. Avelumab is an effective and safe drug for the management of advanced MCC, and its effectiveness appears to be impacted by the number and location of metastases.

Parasites revive hope for cancer therapy

Parasites have attained a life-long stigma of being detrimental organisms with deleterious outcomes. Yet, recently, a creditable twist was verified that can dramatically change our perception of those parasites from being a source of misery to millions of people to a useful anti-cancerous tool. Various parasites have shown promise to combat cancer in different experimental models, including colorectal, lung, and breast cancers, among others. Helminths and protozoan parasites, as well as their derivatives such as Echinococcus granulosus protein KI-1, Toxoplasma gondii GRA15II, and Trypanosoma cruzi calreticulin, have demonstrated the ability to inhibit tumor growth, angiogenesis, and metastasis. This article provides an overview of the literature on various cancer types that have shown promising responses to parasite therapy in both in vitro and in vivo animal studies. Parasites have shown anti-neoplastic activity through a variety of mechanisms that collectively contribute to their anti-cancer properties. These include immunomodulation, inhibition of angiogenesis, and molecular mimicry with cancer cells. This review article sheds light on this intriguing emerging field and emphasizes the value of collaborative multidisciplinary research projects with funding agencies and pharmaceutical companies. Thus, these strategies would secure continuous exploration of this new avenue and accelerate the advancement of cancer therapy research. Although experimental studies are heavily conducted by leaps and bounds, further steps are definitely lagging. Upgrading research from the experimental level to the clinical trial would be a wise progression toward efficient exploitation of the anti-neoplastic capabilities of parasites, ultimately saving countless lives.

Biomarker Analyses Investigating Disease Biology and Associations with Outcomes in the JAVELIN Merkel 200 Trial of Avelumab in Metastatic Merkel Cell Carcinoma

PURPOSE

Avelumab (anti-PD-L1) became the first approved treatment for metastatic Merkel cell carcinoma (mMCC) based on results from the phase II JAVELIN Merkel 200 trial. In this study, we report exploratory biomarker analyses from the trial.

PATIENTS AND METHODS

Patients with mMCC (n = 88) with or without prior first-line chemotherapy received avelumab 10 mg/kg every 2 weeks. We conducted analyses on somatic mutations, mutational signatures, and tumor mutational burden using paired whole-exome sequencing. Additionally, we examined gene and gene set expression, immune content from RNA sequencing profiles, as well as tumor PD-L1 and CD8 statuses from IHC and CD8 status from digital pathology.

RESULTS

Tumors positive for Merkel cell polyomavirus (MCPyV) were characterized by an absence of driver mutations and a low tumor mutational burden, consistent with previous studies. A novel MCPyV-specific host gene expression signature was identified. MCPyV+ tumors had increased levels of immunosuppressive M2 macrophages in the tumor microenvironment, which seemed to correlate with PD-L1 expression; high CD8+ T-cell density in these tumors did not predict response to avelumab. Conversely, in patients with MCPyV- tumors, higher CD8+ T-cell density seemed to be associated with response to avelumab. Mutations in several genes were associated with treatment outcomes. Compared with tumors sampled before chemotherapy, tumors sampled after chemotherapy had downregulated gene signatures for immune responses, including reduced expression of IFNγ-related pathways. Levels of activated dendritic cells in responding patients were higher in patients assessed after versus before chemotherapy.

CONCLUSIONS

Exploratory analyses provide insights into mMCC biology and potential associations with response to avelumab. Chemotherapy seems to negatively modulate the immune microenvironment.

Adverse Event Assessment of Upadacitinib: A Pharmacovigilance Study Based on the FAERS Database

PURPOSE

Upadacitinib, a Janus kinase (JAK) inhibitor, has been approved by the FDA to treat various autoimmune conditions. This study assessed its adverse events by analyzing reports from the FDA Adverse Event Reporting System (FAERS).

METHODS

FAERS data from Q3 2019 to Q4 2023 were extracted, and disproportionality analyses were conducted using four statistical measures, reporting odds ratio, proportionate reporting ratio, Bayesian confidence propagation neural network, and empirical Bayesian geometric mean.

RESULTS

A total of 6 879 398 adverse event reports were collected, with 37 700 reports identifying upadacitinib as the "primary suspected." These reports involved 24 system organ classes and 246 preferred terms that met the criteria across all four algorithms. The distribution of adverse events was assessed separately for female and male patients. Further analysis of the top 25 preferred terms revealed that, although the system organ classes were similar between sexes, the specific adverse events differed. The adverse events were analyzed by gender, showing musculoskeletal and skin disorders were prevalent and severe in male patients, while musculoskeletal issues, infections, and abnormal laboratory tests were common in female patients. Unexpected events like trigger finger, biliary sepsis, and serious events such as oral neoplasm were also identified.

CONCLUSION

This study provides real-world evidence for the safety evaluation of upadacitinib and underscores the need to monitor sex-specific adverse events. Future prospective studies are necessary to confirm these pharmacovigilance findings.

Impact of the adjunction of a short video to an original article for the recognition of newly described tumor entities in pathology: An interventional prospective study

CONTEXT

Merkel cell carcinoma diagnosis is often based on microscopic examination by pathologists. While histopathologic diagnosis primarily hinges on conscious and analytical cognition, the pathologist's decision-making process is also influenced by a rapid "gist" or "gestalt" approach. In this study, using cases of Merkel cell carcinoma as a model, we aim to assess how pathologists' viewing short videos containing conceptual clues and visual aids, in conjunction with reading an original article as a reference, may enhance their diagnostic performance.

METHOD

Sixteen pathologists were included in the present work. After participants had read the original article, their ability to distinguish Merkel cell polyomavirus (MCPyV)+ and MCPyV- Merkel cell carcinoma cases was evaluated on a first preliminary series of 20 cases. Following this test, the participants watched the video and then evaluated a second "experimental" series of 20 independent cases.

RESULTS

After reading the original article, for each case, a median number of 12 participants (75%, Q1-Q3: 10-13) classified the specimen in the correct category (92 incorrect answers in the whole series). An important interobserver variability was observed in this setting (Kappa coefficient = 0.465). By contrast, following the video, all cases were correctly classified by most of the participants, with only 12 incorrect answers on the whole series and excellent interobserver reproducibility (Kappa coefficient = 0.846).

CONCLUSION

Our study demonstrated that providing a short video together with an original article may enhance pathologists' performance in diagnosing Merkel cell carcinoma.

Exploring the effects of Merkel cell polyomavirus T antigens expression in REH and MCC13 cells by methylome and transcriptome profiling

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer with a tripled incidence in the US and Europe over the past decade. Around 80% of MCC is linked to Merkel cell polyomavirus, but the cell of origin remains unknown. We stably introduced Merkel cell polyomavirus (MCPyV)-sT) and LT antigens to MCC13 and REH cell lines, analyzing DNA methylation and gene transcriptional regulation. Gene ontology analysis assessed MCPyV effects, and integrative analysis correlated gene expression and methylation. Expression patterns were compared with 15 previously sequenced primary MCCs. We found that MCPyV-LT induces DNA methylation changes in both cell lines, while MCPyV-sT only affected REH cells. Greater gene expression changes are observed in MCC13 cells, with upregulated genes associated with cellular components and downregulated genes related to biological processes. Integrative analysis of differentially expressed genes (DEG) and differentially methylated regions (DMR) of REH cell lines revealed that no genes were commonly methylated and differentially expressed. The study compared DEGs and DMG in MCC13 and REH cells to overlapping genes in MCPyV-positive cell lines (MKL1, MKL2, and WaGa), identifying hypomethylated genes in the gene body and hypermethylated genes at TSS1500. GO analysis of the two cell lines showed that MCPyV-TAs can downregulate genes in MHC-I pathways; this downregulation offers a target that can be used to create novel and efficient MCC immunotherapy approaches. Finally, it was confirmed that MCPyV-LT controls gene expression in MCC tissues using an integrative investigation of DNA methylation and gene expression.

Targeted therapy and immunotherapy for orbital and periorbital tumors: a major review

Traditionally, for patients who are poor candidates for surgery and/or radiotherapy, palliative chemotherapy is often offered but with significant toxic side effects. However, recent advancements in our understanding of tumor biology and molecular genetics have brought new understanding to the molecular pathways of certain tumors and cancers. This has ushered in a new era of precision medicine specific to a tumor or cancer treatment pathway (targeted therapy) or directed to host-tumor responses (immunotherapy). This article will focus on recent updates in the application of available targeted and immunotherapy for managing orbital and periorbital tumors and tumor-like conditions, which include cutaneous basal cell carcinoma, cutaneous squamous cell carcinoma, cutaneous melanoma, Merkel cell carcinoma, sebaceous gland carcinoma, solitary fibrous tumor, dermatofibrosarcoma protuberans, orbital meningioma, neurofibromatosis, Langerhans cell histiocytosis, ocular adnexal lymphoma, orbital lymphatic malformation, and adenoid cystic carcinoma.

PRAME Expression in Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine tumor of the skin. Risk factors include extensive sun damage, infection with Merkel cell polyomavirus, and an immunocompromised state. PRAME, also known as preferentially expressed antigen in melanoma, is a cancer-testis antigen recently found to be a useful diagnostic tool in the workup of melanocytic neoplasms. However, the expression pattern of PRAME in Merkel cell carcinoma is unknown. In this study, we examine PRAME expression in Merkel cell carcinoma and explore its prognostic implications. The institutional archives at the University of Virginia were used to search for tumors classified as Merkel cell carcinoma from 2004 to 2022. All potential cases were reviewed to confirm the diagnosis, and electronic medical records were searched for clinical and demographic data. Tumors were subsequently immunostained for PRAME and Merkel cell polyomavirus. Cox proportional hazards regression models were used to estimate relative (all-cause) survival of PRAME positivity and MCPyV positivity in our study as well as MCC-specific survival of PRAME positivity. Univariate and multivariable models were created for each outcome related to all-cause survival. A total of 39 cases were included in the study. Twenty-eight percent (11 cases) demonstrated strong PRAME expression, and 27% of cases were positive for Merkel cell polyomavirus. There was no statistically significant correlation between PRAME expression and virus positivity. With respect to PRAME, the adjusted all-cause mortality hazard ratio was 11.4 (95% CI: 1.8, 70.8). The unadjusted MCC-specific hazard ratio was 4.6 (95% CI: 0.8, 27.5). The adjusted hazard ratio pertaining to Merkel cell polyomavirus infection was 0.25 (95% CI: 0.02, 2.96). In this limited cohort, PRAME expression appears to correlate with worse outcomes in Merkel cell carcinoma.

Merkel Cell Carcinoma Brain Metastasis Mimicking Stroke: A Case Report

Merkel cell carcinoma (MMC) is a rare cutaneous neuroendocrine cancer that has the potential to metastasize. However, brain metastasis is infrequent in this type of cancer. We presented a case of a 55-year-old female patient with MCC who had a skin lesion on her right thigh. The cancer had spread to the brain and caused the development of splenic nodules. The patient also experienced intractable headaches and right-sided body weakness, which mimicked the symptoms seen in stroke cases. This case highlights the unusual clinical features and emphasizes the need for further investigation and understanding of the behavior of MCC, particularly in relation to metastasis patterns and associated symptoms.

Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine skin cancer that is highly radiosensitive and immunogenic. Immunotherapy is the primary treatment of advanced disease, and immune checkpoint inhibitors show promise as neoadjuvant or adjuvant therapy in patients with high-risk resectable MCC. Emerging biomarkers of tumor burden are becoming increasingly important in identifying high-risk patients and in post-treatment surveillance. Further research is needed to determine the optimal duration of anti-PD-(L)1 treatment and second-line options for patients with MCC refractory to immunotherapy. This review covers the characteristics and management of MCC including recent innovations and areas of active investigation.

Survival outcomes in patients with de novo metastatic Merkel cell carcinoma according to site of metastases

Introduction

Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine malignancy of the skin with a predilection for metastases. This study investigates the clinical outcomes in patients presenting with de novo Stage IV MCC according to the metastatic site(s) at presentation.

Materials and methods

Patients who presented with one or more sites of distant metastatic MCC at initial diagnosis between 2009 and 2023 were identified. The presence or absence of one or more metastases in each organ was categorized for each patient at the time of diagnosis. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method. Competing risk analysis was used to estimate the cumulative occurrence risk of MCC-specific death. Fisher's exact test was used for response rate analysis. Results were considered statically significant if p < 0.05.

Results

Thirty-four patients presented with de novo distant metastatic MCC. There was no association between the number of metastatic sites at diagnosis and OS (p= 0.58), PFS (p=0.79), or response rates (p=0.53). However, the presence of bone metastases was associated with significantly shorter OS (8.2 versus 25.2 months, HR: 2.4, 95% CI 1.01-5.7, p= 0.04). MCC-specific death in patients with lymph node metastases was significantly lower than in patients without (HR: 0.28, 95% CI: 0.09-0.87, p= 0.013). The presence of bone metastases tended to associate with an increased risk of MCC-specific death, although not statistically significant. The location of metastases was not associated with the response rate to first-line treatment. There was no significant association between site of metastases and PFS.

Conclusion

In this cohort of patients with de novo metastatic MCC, the presence of bone metastases, but not the number of organs involved, was associated with significantly worse OS. The presence of lymph node metastases was associated with lower MCC-specific death. Further research is warranted in larger cohorts to investigate the impact of the location of metastases on clinical outcomes.

Durability of response to immune checkpoint blockade following treatment discontinuation and efficacy of rechallenge in advanced Merkel cell carcinoma

BACKGROUND

Advanced Merkel cell carcinoma (MCC) has a high response rate to immune checkpoint blockade (ICB) therapy, but the durability of responses once treatment is discontinued remains unclear. We therefore reviewed the long-term outcomes of advanced patients with MCC who discontinued ICB treatment after achieving favorable initial response.

METHODS

We performed a retrospective review of advanced patients with MCC treated at a single high-volume referral center, including all patients who received at least one dose of anti-programmed death receptor 1 (ligand) monotherapy for unresectable or metastatic disease, achieved stable disease (SD) or better, and discontinued treatment for a reason other than disease progression.

RESULTS

Of 195 advanced patients with MCC treated with ICB, we identified 45 who met the study criteria. Of these, 21 (46.6%) had a complete response (CR) to initial ICB treatment, 23 (51.1%) a partial response and 1 (2.2%) SD. 25 (55.6%) patients discontinued ICB electively and 20 (44.4%) discontinued due to toxicity. In total, 21 of the 45 patients (46.6%) experienced disease progression at a median of 11.3 months (range 2.1-22.7 months) from ICB cessation. There was a lower rate of progression in patients who achieved CR versus non-CR (23.8% vs 66.7%, p=0.006) and a trend towards a lower rate in those who discontinued electively versus due to toxicity (36.0% vs 60.0%, p=0.14). There was a higher risk for progression in patients with viral positive MCC compared with viral negative MCC (75.0 vs 30.8%, p=0.02). 16 of the 21 patients who experienced progression were retreated subsequently with ICB therapy, including both single-agent rechallenge (12) and escalation to combination ICB (4). 11 of 15 evaluable ICB-retreated patients (73.3%) achieved an objective response.

CONCLUSIONS

Patients with advanced MCC have a substantial risk of disease progression following treatment discontinuation despite initial favorable ICB response, particularly in those that achieve less than a CR. Most of these patients maintain sensitivity to retreatment with the same drug class. Virus-positive MCC may be a risk factor for post-discontinuation relapse, which should be validated in future studies.

Agonists, Antagonists and Receptors of Somatostatin: Pathophysiological and Therapeutical Implications in Neoplasias

Somatostatin is a peptide that plays a variety of roles such as neurotransmitter and endocrine regulator; its actions as a cell regulator in various tissues of the human body are represented mainly by inhibitory effects, and it shows potent activity despite its physiological low concentrations. Somatostatin binds to specific receptors, called somatostatin receptors (SSTRs), which have different tissue distributions and associated signaling pathways. The expression of SSTRs can be altered in various conditions, including tumors; therefore, they can be used as biomarkers for cancer cell susceptibility to certain pharmacological agents and can provide prognostic information regarding disease evolution. Moreover, based on the affinity of somatostatin analogs for the different types of SSTRs, the therapeutic range includes conditions such as tumors, acromegaly, post-prandial hypotension, hyperinsulinism, and many more. On the other hand, a number of somatostatin antagonists may prove useful in certain medical settings, based on their differential affinity for SSTRs. The aim of this review is to present in detail the principal characteristics of all five SSTRs and to provide an overview of the associated therapeutic potential in neoplasias.

Neuroendocrine Neoplasms

Neuroendocrine neoplasms (NENs), also known as neuroendocrine tumors (NETs), are rare tumors derived from cells with characteristics of both nerve and endocrine cells. The clinical presentation, diagnosis, and treatment of NENs vary significantly depending on the type, location, whether the neoplasm is hormonally functional, how aggressive it is, and whether it has metastasized to other parts of the body. This article provides an overview of specific types of NETs, clinical presentations and related syndromes, diagnosis, and approach to management of common NENs.

Analyses of combined Merkel cell carcinomas with neuroblastic components suggests that loss of T antigen expression in Merkel cell carcinoma may result in cell cycle arrest and neuroblastic transdifferentiation

Merkel cell carcinoma (MCC) is an aggressive skin cancer frequently caused by genomic integration of the Merkel cell polyomavirus (MCPyV). MCPyV-negative cases often present as combined MCCs, which represent a distinctive subset of tumors characterized by association of an MCC with a second tumor component, mostly squamous cell carcinoma. Up to now, only exceptional cases of combined MCC with neuroblastic differentiation have been reported. Herein we describe two additional combined MCCs with neuroblastic differentiation and provide comprehensive morphologic, immunohistochemical, transcriptomic, genetic and epigenetic characterization of these tumors, which both arose in elderly men and appeared as an isolated inguinal adenopathy. Microscopic examination revealed biphasic tumors combining a poorly differentiated high-grade carcinoma with a poorly differentiated neuroblastic component lacking signs of proliferation. Immunohistochemical investigation revealed keratin 20 and MCPyV T antigen (TA) in the MCC parts, while neuroblastic differentiation was confirmed in the other component in both cases. A clonal relation of the two components can be deduced from 20 and 14 shared acquired point mutations detected by whole exome analysis in both combined tumors, respectively. Spatial transcriptomics demonstrated a lower expression of stem cell marker genes such as SOX2 and MCM2 in the neuroblastic component. Interestingly, although the neuroblastic part lacked TA expression, the same genomic MCPyV integration and the same large T-truncating mutations were observed in both tumor parts. Given that neuronal transdifferentiation upon TA repression has been reported for MCC cell lines, the most likely scenario for the two combined MCC/neuroblastic tumors is that neuroblastic transdifferentiation resulted from loss of TA expression in a subset of MCC cells. Indeed, DNA methylation profiling suggests an MCC-typical cellular origin for the combined MCC/neuroblastomas. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Merkel Cell Carcinoma With Extensive Bone Marrow Metastasis and Peripheral Blood Involvement: A Case Report With Immunohistochemical and Mutational Studies

Merkel cell carcinoma (MCC) is a rare, highly aggressive skin cancer of neuroendocrine origin that is typically associated with either the presence of Merkel cell polyomavirus or chronic exposure to ultraviolet (UV) light. We report a case of relapsed MCC that presented with new symptoms of fatigue, back pain, and myeloid left shift identified during scheduled follow-up. The patient was found to have circulating neoplastic cells in the peripheral blood and bone marrow metastasis. Immunohistochemistry for synaptophysin, CD56, INSM-1, CK20, CD117 were positive, whereas CD34, TdT, Chromogranin, CD10, myeloperoxidase, CD3 and CD19 were negative. Flow cytometry of the peripheral blood confirmed the presence of an abnormal nonhematopoietic cell population expressing CD56 positivity. A next-generation sequencing (NGS) panel revealed the presence of variants in RB1, TP53, and other genes, some of which have not been previously described in MCC. This rare presentation highlights the challenges in the diagnosis and management of MCC.

Merkel Cell Polyomavirus-Pathophysiology and Treatment in the Era of Gene-Targeted Therapies

Merkel cell polyomavirus (MCPyV) is a significant contributor to the development of Merkel cell carcinoma (MCC), an aggressive skin cancer with high recurrence and a low survival rate. In fact, it is the deadliest skin cancer. The precise routes of transmission for MCPyV-positive MCC remain unclear, but several factors may trigger its development. Conventional treatments for MCC are not highly effective, especially in patients with metastasis, with a clear need for new treatment options. Gene-targeted therapies hold great promise for the treatment of MCC, including the use of siRNA and CRISPR/Cas (C/Cas) but critically none have yet been translated into clinical trials. Validating this approach is the fact that several siRNA products are already FDA licenced, while C/Cas has entered clinical trial, albeit for conditions other than MCC. There are many challenges that must be overcome to move from preclinical research to the clinic. In this review, we provide a comprehensive summary of the current understanding of MCC, with a particular focus on MCPyV-positive MCC, and the status of gene-targeted therapies. Additionally, we discuss the major obstacles that impede MCC research and explore future prospects.

The interplay between persistent pathogen infections with tumor microenvironment and immunotherapy in cancer

BACKGROUND

Chronic infections by pathogenic microorganisms play a significant role in cancer development, disrupting the body's immune system and microenvironment. This interference impairs the body's ability to eliminate these microorganisms promptly, allowing them to persist by evading immune defenses.

AIMS

This study aimed to explore how chronic pathogenic infections influence the immune microenvironment, impacting tumorigenesis, cancer progression, and treatment strategies. Additionally, it seeks to investigate the effects of these infections on specific immune checkpoints and identify potential targets for immunotherapy.

METHODS

We conducted searches, readings, and detailed analyses of key terms in databases like PubMed and Web of Science to evaluate the impact of chronic infections by pathogenic microorganisms on the immune microenvironment.

RESULTS

Our analysis demonstrates a significant association between persistent chronic infections by pathogenic microorganisms and tumorigenesis. Notable impacts on the immune microenvironment include changes in immune cell function and the regulation of immune checkpoints, offering insights into potential targets for cancer immunotherapy.

DISCUSSION

This study highlights the complex relationship between chronic infections and cancer development, presenting new opportunities for cancer immunotherapy by understanding their effects on the immune microenvironment. The influence of these infections on immune checkpoints emphasizes the crucial role of the immune system in cancer treatment.

CONCLUSION

Chronic infections by pathogenic microorganisms greatly affect the immune microenvironment, tumorigenesis, and cancer treatment. Unraveling the underlying mechanisms can unveil potential targets for immunotherapy, improving our comprehension of the immune response to cancer and potentially leading to more effective cancer treatments in the future.

The Role of the Large T Antigen in the Molecular Pathogenesis of Merkel Cell Carcinoma

The large T antigen (LT) of the Merkel cell polyomavirus (MCPyV) is crucial for Merkel cell carcinoma (MCC), a rare but very aggressive form of neuroendocrine skin cancer. The clonal integration of MCPyV DNA into the host genome is a signature event of this malignancy. The resulting expression of oncogenes, including the small T (sT) antigen and a truncated form of the LT (truncLT), directly contribute to carcinogenesis. The truncation of the C-terminus of LT prevents the virus from replicating due to the loss of the origin binding domain (OBD) and the helicase domain. This precludes cytopathic effects that would lead to DNA damage and ultimately cell death. At the same time, the LxCxE motif in the N-terminus is retained, allowing truncLT to bind the retinoblastoma protein (pRb), a cellular tumor suppressor. The continuously inactivated pRb promotes cell proliferation and tumor development. truncLT exerts several classical functions of an oncogene: altering the host cell cycle, suppressing innate immune responses to viral DNA, causing immune escape, and shifting metabolism in favor of cancer cells. Given its central role in MCC, the LT is a major target for therapeutic interventions with novel approaches, such as immune checkpoint inhibition, T cell-based immunotherapy, and cancer vaccines.

Novel therapeutic agents in clinical trials: emerging approaches in cancer therapy

Novel therapeutic agents in clinical trials offer a paradigm shift in the approach to battling this prevalent and destructive disease, and the area of cancer therapy is on the precipice of a trans formative revolution. Despite the importance of tried-and-true cancer treatments like surgery, radiation, and chemotherapy, the disease continues to evolve and adapt, making new, more potent methods necessary. The field of cancer therapy is currently witnessing the emergence of a wide range of innovative approaches. Immunotherapy, including checkpoint inhibitors, CAR-T cell treatment, and cancer vaccines, utilizes the host's immune system to selectively target and eradicate malignant cells while minimizing harm to normal tissue. The development of targeted medicines like kinase inhibitors and monoclonal antibodies has allowed for more targeted and less harmful approaches to treating cancer. With the help of genomics and molecular profiling, "precision medicine" customizes therapies to each patient's unique genetic makeup to maximize therapeutic efficacy while minimizing unwanted side effects. Epigenetic therapies, metabolic interventions, radio-pharmaceuticals, and an increasing emphasis on combination therapy with synergistic effects further broaden the therapeutic landscape. Multiple-stage clinical trials are essential for determining the safety and efficacy of these novel drugs, allowing patients to gain access to novel treatments while also furthering scientific understanding. The future of cancer therapy is rife with promise, as the integration of artificial intelligence and big data has the potential to revolutionize early detection and prevention. Collaboration among researchers, and healthcare providers, and the active involvement of patients remain the bedrock of the ongoing battle against cancer. In conclusion, the dynamic and evolving landscape of cancer therapy provides hope for improved treatment outcomes, emphasizing a patient-centered, data-driven, and ethically grounded approach as we collectively strive towards a cancer-free world.