Merkel Cell Carcinoma-Update on Diagnosis, Management and Future Perspectives

A landscape of checkpoint blockade resistance in cancer: underlying mechanisms and current strategies to overcome resistance

The discovery of immune checkpoints and the development of immune checkpoint inhibitors (ICI) have achieved a durable response in advanced-stage cancer patients. However, there is still a high proportion of patients who do not benefit from ICI therapy due to a lack of response when first treated (primary resistance) or detection of disease progression months after objective response is observed (acquired resistance). Here, we review the current FDA-approved ICI for the treatment of certain solid malignancies, evaluate the contrasting responses to checkpoint blockade in different cancer types, explore the known mechanisms associated with checkpoint blockade resistance (CBR), and assess current strategies in the field that seek to overcome these mechanisms. In order to improve current therapies and develop new ones, the immunotherapy field still has an unmet need in identifying other molecules that act as immune checkpoints, and uncovering other mechanisms that promote CBR.

Implications of intrinsic disorder and functional proteomics in the merkel cell polyomavirus life cycle

Infection with merkel cell polyomavirus (MCPyV) is implicated in the development of merkel cell carcinoma (MCC), a rare but aggressive skin cancer. MCC has a mortality rate near 50%, and incidence has been rapidly increasing in recent decades, making development of improved treatment strategies critical to addressing its growing social burden. The parallel increasing necessity for novel research to better understand MCPyV pathogenesis has prompted numerous studies in recent years, yet the role of intrinsic disorder in MCPyV proteins remains unexplored. This study carries out computational characterization of intrinsic disorder within the MCPyV proteome and suggests mechanisms that may contribute to the oncogenicity of the virus to invade and hijack host immune systems. Our analysis finds that significant levels of intrinsic disorder are present in proteins LT, ALTO, 57kT, and VP1, and suggests that regions of sT may also contain large, disordered regions. The investigation further shows correlation of disorder propensity with the outputs for functional predictors of eukaryotic linear motifs (ELMs), molecular recognition features (MoRFs), and propensity for liquid-liquid phase separation (LLPS). Our findings indicate that MCPyV may use disorder and phase condensation to alter viral function that may accentuate or provide the basis for oncogenic activities. It is intended that this study will inform future experimental validation efforts around the phase separation capacity of MCPyV and its host protein-protein interactions. Furthermore, we hope to inform other investigators on the potential role of disorder in the MCPyV life cycle toward ultimately progressing the development of novel therapeutic agents.

Advancing Treatment Options for Merkel Cell Carcinoma: A Review of Tumor-Targeted Therapies

Although rare, Merkel cell carcinoma (MCC) is a highly aggressive and increasingly prevalent neuroendocrine cancer of the skin. While current interventions, including surgical resection, radiation, and immunotherapy have been employed in treating many patients, those who remain unresponsive to treatment are met with sparse alternatives and a grim prognosis. For this reason, it is of interest to expand the repertoire of available therapies for MCC patients who remain resistant to current primary interventions. Recently, our improved mechanistic understanding of aberrant cell signaling observed in both MCPyV-positive and -negative MCC has facilitated exploration into several small molecules and inhibitors, among them receptor tyrosine kinase inhibitors (TKIs) and somatostatin analogs (SSAs), both of which have positively improved response rates and reduced tumor volumes upon application to treatment of MCC. The introduction of such targeted therapies into treatment protocols holds promise for more personalized care tailored towards patients of diverse subtypes, thereby improving outcomes and mitigating tumor burden, especially for treatment-resistant individuals. In this review, we characterize recent findings surrounding targeted treatments that have been applied to MCC and provide an overview of emerging perspectives on translatable options that can be further developed to offer additional therapeutic avenues for patients with the disease.

Double Primary Cancers of Earlobe Merkel Cell Carcinoma and Lung Adenocarcinoma

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine carcinoma with a high rate of metastasis. MCC is rarely suspected during clinical examination, thus requiring biopsy to establish a pathologic diagnosis. In addition, MCC sometimes occurs in double primary cancers. Although there have been reviews on double primary cancers, only a few cases involving MCC have been described. Herein, we report a case of a 54-year-old female patient who presented to our clinic with a diagnosis of earlobe MCC following an excisional biopsy performed by another clinic. Further evaluation, including chest imaging, revealed a mass in the lung. The patient underwent a wide excision of the right earlobe, and video-assisted thoracic surgery on the lung. Pathology confirmed MCC in the right earlobe and adenocarcinoma in the lung. The patient underwent postoperative adjuvant chemotherapy followed by radiotherapy. Up to this point, 3 years after the surgery, there has been no evidence of recurrence.

Current Progress in Vaccines against Merkel Cell Carcinoma: A Narrative Review and Update

Merkel cell carcinoma is a rare, aggressive skin cancer that mainly occurs in elderly and immunocompromised patients. Due to the success of immune checkpoint inhibition in MCC, the importance of immunotherapy and vaccines in MCC has increased in recent years. In this article, we aim to present the current progress and perspectives in the development of vaccines for this disease. Here, we summarize and discuss the current literature and ongoing clinical trials investigating vaccines against MCC. We identified 10 articles through a PubMed search investigating a vaccine against MCC. From the international clinical trial database Clinical.Trials.gov, we identified nine studies on vaccines for the management of MCC, of which seven are actively recruiting. Most of the identified studies investigating a vaccine against MCC are preclinical or phase 1/2 trials. The vaccine principles mainly included DNA- and (synthetic) peptide-based vaccines, but RNA-based vaccines, oncolytic viruses, and the combination of vaccines and immunotherapy are also under investigation for the treatment of MCC. Although the management of MCC is changing, when compared to times before the approval of immune checkpoint inhibitors, it will still take some time before the first MCC vaccine is ready for approval.

Merkel-cell carcinoma: ESMO-EURACAN Clinical Practice Guideline for diagnosis, treatment and follow-up

•This ESMO Clinical Practice Guideline provides key recommendations for managing Merkel-cell carcinoma (MCC). •Recommendations are based on available scientific data and the multidisciplinary group of experts’ collective opinion. •The guideline covers clinical and pathological diagnosis, staging and risk assessment, treatment and follow-up. •Algorithms for the management of locoregional and inoperable/metastatic disease are provided. •A multidisciplinary team with a high level of expertise in MCC should diagnose and make decisions about therapy.

Merkel Cell Carcinoma on the Face: Case Report

Merkel cell carcinoma (MCC) is a rare primary neuroendocrine skin tumor that presents as a flesh-colored or bluish-red nodule on the face, neck, or head. Long-term ultraviolet radiation exposure and Merkel cell polyomavirus are associated with MCC pathogenesis. We present a case of MCC on the right cheek in a male patient aged 87 years. Our primary goal in presenting the case is to bring MCC, which is a diagnostic challenge, to the notice of dermatologists and oncologists, as early detection and prompt treatment are important. The patient had a significant past medical history, including diabetes mellitus, hypertension, dyslipidemia, stage 3 chronic kidney disease, benign prostatic hyperplasia, chronic hyponatremia, acute pancreatitis, essential thrombocytosis on hydroxyurea, and ischemic heart disease. The patient presented with a mildly swollen right upper lip showing a poorly defined, relatively homogeneous subcutaneous lesion with a history of persistence for 1.5 months. The clinical examination revealed a 5 × 3-cm nodular lesion on the right side of the cheek with swelling of the right upper lip. Immunohistochemistry markers and histopathological features confirmed the diagnosis of MCC. The patient was referred to the oncology department for further management. MCC of the skin is an aggressive lesion with a high risk of metastasis and recurrence, which is more common in immunocompromised people. Prompt management and treatment of MCC is essential because if left untreated, it can spread to other parts of the body and can also metastasize to lymph nodes and other organs. The patient is 87 years old and has a significant past medical history of diabetes mellitus, hypertension, dyslipidemia, chronic kidney disease stage 3, benign prostatic hyperplasia, chronic hyponatremia, acute pancreatitis, essential thrombocytosis on hydroxyurea, and ischemic heart disease. Currently, the patient presented with a mildly swollen right upper lip showing a poorly defined, relatively homogenous subcutaneous lesion with a history of persistence for 1.5 months. The clinical examination revealed a 5x3 cm nodular lesion on the right side of the cheek with swelling of the right upper lip. Immunohistochemistry markers results and histopathological features confirmed the diagnosis of Merkel cell carcinoma. The patient was referred to the oncology department for further management. Merkel cell carcinoma of the skin is an aggressive lesion with a high risk of metastasis and recurrence, which is more common in immunocompromised people. Prompt management and treatment of Merkel cell carcinoma is essential because if left untreated, it can spread to other parts of the body and can also metastasize to lymph nodes and other organs.

The Neutrophil-to-Lymphocyte Ratio as a Biomarker in Cutaneous Oncology: A Systematic Review of Evidence beyond Malignant Melanoma

With the ongoing progress of basic research along with the introduction of new pharmaceutical options spanning almost all therapeutic areas, the need for biomarkers that will be implemented into the personalized medical approach is higher than ever. Their use can be incorporated into clinical practice and can be applied to the classification of disorders and the evaluation of disease severity but also to the monitoring of the progress of therapeutic/pharmaceutical interventions. This systematic review collects the findings of hematologic biomarkers in various cutaneous malignancies, excluding malignant melanoma, to support their potential use in the prognosis but also in the assessment of therapeutic strategies for the specific category of skin disorders.

Imaging of Merkel cell carcinoma of the eyelid: A case report

Merkel cell carcinoma (MCC) is a rare primary neuroendocrine carcinoma commonly found in older adults in areas of the skin that are susceptible to ultraviolet ray damage. The current study reports the case of a 79-year-old woman who presented to the Affiliated Hospital of Zunyi Medical University (Zunyi, China) with a painless lump in the lower eyelid of the left eye accompanied by photophobic tears for 4 months. Head computed tomography (CT) and magnetic resonance imaging (MRI) showed a space-occupying lesion ~2.8×2.4 cm in size outside the left orbital muscle cone, which was poorly demarcated from the surrounding normal tissues. Markedly intense and tortuous walking vascular shadows were observed within the tumor tissues. Fluorine-18-fluorodeoxyglucose positron emission tomography (18F-FDG PET)/CT revealed increased 18F-FDG uptake in the corresponding lesions. Based on these imaging features, a malignant tumor was suspected. The patient subsequently underwent surgery. Postoperative pathology and immunohistochemistry revealed MCC. The clinical presentation of MCC is usually a painless soft-tissue nodule or mass that grows rapidly over a short period and is flesh-colored, bluish red or purple. A slightly hyperdense mass on CT, with equal T1-weighted and slightly longer T2-weighted MRI signals, and mild enhancement on contrast-enhanced scans, accompanied by significantly enhanced distorted vascular shadows and increased 18F-FDG uptake on PET/CT, are valuable in the diagnosis of eyelid MCC.

Rare but Still There: An Interesting Case of Cytokeratin 20-Negative Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) of the skin is a rare and aggressive primary neuroendocrine tumor that mainly involves sun-exposed areas and can metastasize to other parts of the body. Due to varied clinical features and the sharing of similar histological features with other neuroendocrine tumors, diagnosis can be challenging. Therefore, immunohistochemistry plays an important role in diagnosis, and the characteristic perinuclear staining with cytokeratin 20 (CK 20) helps to differentiate it from other morphologically similar tumors, especially metastatic small cell carcinoma of the lung. We describe an interesting case of a 78-year-old female who was referred by a general practitioner (GP) with a few months' history of asymptomatic, rapidly enlarging, erythematous, nodular lesion on her left upper arm. Due to clinical findings and the location of the lesion on the sun-exposed area, wide differential diagnoses were considered. The lesion was excised for histological diagnosis. Surprisingly, morphological features favour the diagnosis of a neuroendocrine tumor. However, histological features including immunohistochemistry rendered it difficult to differentiate between primary cutaneous neuroendocrine carcinoma (Merkel cell CA) and metastatic small cell carcinoma of the lung due to the lack of specific and sensitive marker of CK 20 on immunohistochemistry. Subsequently, the patient had computer tomography of the chest/abdomen and pelvis (CTTAP) and positron emission tomography (PET) scans to rule out underlying primary malignancy. The case was also discussed at local and specialist skin multidisciplinary team meetings (MDT) including neuroendocrine MDT and a consensus diagnosis of Merkel cell carcinoma of the skin with negative CK 20 was established.

Neoplasms of the Ear Canal

Primary EAC neoplasms include benign and malignant lesions of bony, glandular or cutaneous origin. Small, benign slow growing bony neoplasms are often asymptomatic, diagnosed incidentally and might not require intervention. Both malignant and benign neoplasms of cutaneous and glandular origin can present with symptoms of chronic otitis externa, leading to delays in diagnosis. Prompt biopsy of soft tissue lesions associated with non-resolving otitis externa are warranted. Local and regional imaging is helpful to understand disease extent and origin, but even early-stage malignant neoplasms require aggressive surgical treatment.

Advancing Immunotherapies for HPV-Related Cancers: Exploring Novel Vaccine Strategies and the Influence of Tumor Microenvironment

The understanding of the relationship between immunological responses and cancers, especially those related to HPV, has allowed for the study and development of therapeutic vaccines against these neoplasias. There is a growing number of studies about the composition and influence of the tumor microenvironment (TME) in the progression or establishment of the most varied types of cancer. Hence, it has been possible to structure immunotherapy approaches based on therapeutic vaccines that are even more specific and directed to components of TME and the immune response associated with tumors. Among these components are dendritic cells (DCs), which are the main professional antigen-presenting cells (APCs) already studied in therapy strategies for HPV-related cancers. On the other hand, tumor-associated macrophages are also potential targets since the profile present in tumor infiltrates, M1 or M2, influences the prognosis of some types of cancer. These two cell types can be targets for therapy or immunomodulation. In this context, our review aims to provide an overview of immunotherapy strategies for HPV-positive tumors, such as cervical and head and neck cancers, pointing to TME immune cells as promising targets for these approaches. This review also explores the potential of immunotherapy in cancer treatment, including checkpoint inhibitors, cytokine immunotherapies, immunotherapy vaccines, and cell therapies. Furthermore, it highlights the importance of understanding the TME and its effect on the design and achievement of immunotherapeutic methods.