Merkel cell carcinoma - recent advances in the biology, diagnostics and treatment

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.

A Rare Case of Metastatic Merkel Cell Carcinoma to the Stomach and Pancreas Presenting With Upper Gastrointestinal Bleeding and Obstructive Jaundice

Merkel cell carcinoma (MCC) is a rare and aggressive primary neuroendocrine tumor of the skin. Gastrointestinal (GI) metastasis in MCC is uncommon. We present a case of MCC with metastasis to the stomach, duodenum, and pancreas presenting with melena and obstructive jaundice. A large, bleeding metastatic mass was identified in the duodenum. Hemostasis was achieved with coil embolization. Endoscopic retrograde cholangiopancreatography with stenting of the common bile duct was performed to relieve the obstruction. Close surveillance with positron emission tomography/computed tomography scan and possible GI endoscopy should be performed in cases with distant metastasis to identify and treat early GI tract lesions.

The role of infectious agents in cancer of the ocular region

The purpose of the study was to investigate the association between infectious agents and the development of cancer in the ocular adnexa. A comprehensive literary study was carried out, reviewing and summarizing previous reports on the topic. A broad range of malignancies of the ocular adnexa are associated with infectious agents. A strong association and possible causal relationship between the infectious agent and the development of ocular adnexal cancer are seen in Merkel cell carcinoma (Merkel cell polyomavirus), Burkitt lymphoma (Epstein-Barr virus) and Kaposi sarcoma (human herpesvirus 8). Infection with Chlamydia psittaci has been associated with the development of extranodal marginal zone B-cell lymphoma in Italy. Human papillomavirus infection has been associated with the development of squamous cell carcinomas of the ocular adnexa, although with a highly variable reported prevalence. By exploring the role of infectious agents in the ocular adnexa and the mechanism by which they contribute to oncogenesis, the diagnostics, management and prevention of these malignancies may also improve. Antibiotic treatment and vaccines against infectious agents may be valuable in future treatment. Additionally, the presence of infectious agents within the tumours may have a prognostic or predictive value.

Merkel cell carcinoma of the thigh: case report and review of the literature

BACKGROUND

Merkel cell carcinoma (MCC) is a kind of cutaneous neuroendocrine cancer with a poor prognosis. It is characterized by a high rate of recurrence and metastases, including distant metastases and regional nodal metastases. Clinically, MCC often manifests as obvious single painless hard nodules visible in sun irradiation of diameter <2 cm and not uncommonly >2 cm, with rapid growth and metastases, especially lymph node metastases. Due to the aspecific nature of MCC, it is often confused with other skin cancers. Exploring different treatments of MCC is necessary.

CASE PRESENTATION

The current study describes the case of an 86-year-old retired man, who presented with a 2.5×2.0×1.2 cm red nodule on the right thigh, which was initially diagnosed as subcutaneous small cell cancer. Upon histological and immunohistochemical analysis, the tumor was consistent with a diagnosis of MCC.

RESULTS

Antiangiogenic therapy combining endostar and apatinib was administered and a partial response achieved after 2.0 months of treatment, and 6.5 months of progression-free survival was achieved. Overall survival was 13.0 months.

CONCLUSION

We believe that antiangiogenic therapy is an extremely effective treatment for MCC, especially for patients who cannot tolerate chemotherapy and radiotherapy.

Human oncoviruses: Mucocutaneous manifestations, pathogenesis, therapeutics, and prevention: Papillomaviruses and Merkel cell polyomavirus

In 1964, the first human oncovirus, Epstein-Barr virus, was identified in Burkitt lymphoma cells. Since then, 6 other human oncoviruses have been identified: human papillomavirus, Merkel cell polyomavirus, hepatitis B and C viruses, human T-cell lymphotropic virus-1, and human herpesvirus-8. These viruses are causally linked to 12% of all cancers, many of which have mucocutaneous manifestations. In addition, oncoviruses are associated with multiple benign mucocutaneous diseases. Research regarding the pathogenic mechanisms of oncoviruses and virus-specific treatment and prevention is rapidly evolving. Preventative vaccines for human papillomavirus and hepatitis B virus are already available. This review discusses the mucocutaneous manifestations, pathogenesis, diagnosis, treatment, and prevention of oncovirus-related diseases. The first article in this continuing medical education series focuses on diseases associated with human papillomavirus and Merkel cell polyomavirus, while the second article in the series focuses on diseases associated with hepatitis B and C viruses, human T-cell lymphotropic virus-1, human herpesvirus-8, and Epstein-Barr virus.

A case series of Merkel cell carcinoma of the eyelid: a rare entity often misdiagnosed

Merkel cell carcinoma (MCC) is one of the rarest eyelid tumors, with high mortality rate due to lymphatic and metastatic spread. We hereby report six cases of patients with histological diagnosis of MCC referred to our Orbit Unit between 2012 and 2018, focusing on diagnosis, treatment, and subsequent follow up. All patients underwent surgical excision and systemic work-up. Both MCC TNM and eyelid MCC TNM were used to stage lesions. MCC of the eyelid is usually misdiagnosed as benign or other malignant lesions. A prompt examination and a wide local excision are mandatory. A close follow-up of these patients is advised due to high recurrence rate and lymphatic spread.

Detection of oncogenic viruses in water environments by a Luminex-based multiplex platform for high throughput screening of infectious agents

Recent studies documented the detection of viruses strongly associated with human cancer in urban sewages and other water environments worldwide. The aim of this study was to estimate the occurrence of human oncogenic viruses in environmental samples (sewage, river, marine, and pool/spa water) using highly sensitive and specific multiplex bead-based assays (Luminex technology). A total of 33 samples were analysed for 140 oncogenic viral agents, including mucosal and cutaneous human papillomaviruses (HPVs), human polyomaviruses (HPyV), human herpesviruses (HHV) and mouse mammary tumour virus (MMTV). Eighty-eight percent of the samples tested positive for at least one viral pathogen and the simultaneous presence of more than one virus was frequent (mean number of positivities/sample = 3.03). A total of 30 different Alpha, Beta and Gamma HPVs were detected, including mucosal and cutaneous types. The high-risk type HPV16 was the most frequently detected virus, identified in 73% of the samples. Of the 12 HPyVs tested, only two (BKPyV and MCPyV) were detected. At least one of these two was present in 48% of the samples. MMTV was detected in 21% of the samples, while herpesviruses - HHV-6 and HHV-1 - were detected in two samples (6%). The present study is the first to provide a comprehensive picture of the occurrence of oncogenic viruses belonging to different families and species in diverse water environments, and the first to successfully use, in environmental samples, a Luminex-based multiplex platform for high throughput screening of infectious agents. Our findings, showing that oncogenic viruses are ubiquitous in water environments, pave the way for future studies on the fate of these pathogens in water environments as well as on their potential for transmission via the waterborne route.

Avelumab and other recent advances in Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare but aggressive form of skin cancer that occurs in the elderly, is associated with UV radiation and immunosuppression. Initial treatment consists of wide excision with adjuvant radiation. Although the tumor is sensitive to chemotherapy, long-term survival is unusual and there had been no US FDA-approved drugs prior to 2017. The recognition that MCC is associated with the Merkel cell polyomavirus occurs more commonly in immune-compromised patients and tumors express PD-L1 suggested testing immunotherapy. A study of an anti-PD-L1 antibody, avelumab, in chemotherapy-refractory MCC demonstrated a response rate of 31.8% resulting in FDA approval in March 2017 and EMA in September 2017. This review will discuss the disease, role of avelumab and other emerging treatment strategies for MCC.

Oral etoposide in Merkel cell carcinoma

Background

Merkel cell carcinoma (MCC) is a very infrequent and aggressive skin tumor with high recurrence and metastasis rates. MCC treatment is currently not well defined.

Case presentation

We present the case of a 75-year-old woman who was diagnosed with MCC in 2010 and suffered a third relapse in 2012 which could not be treated surgically.

Results

The patient began oral etoposide treatment reaching complete response after eight cycles and receiving a total of 11 cycles. As side effects, the patient suffered from neutropenia, candidiasis and mucositis, but after reducing the dosage to 50% it was well tolerated.

Discussion

Chemotherapy treatment in this setting is poorly defined. In this case, monotherapy treatment with oral etoposide was decided due to the patient's age and comorbidities, achieving a very positive outcome.

Merkel Cell Polyomavirus Small T Antigen Initiates Merkel Cell Carcinoma-like Tumor Development in Mice

Merkel cell carcinoma (MCC) tumor cells express several markers detected in normal Merkel cells, a nonproliferative population of neuroendocrine cells that arise from epidermis. MCCs frequently contain Merkel cell polyomavirus (MCPyV) DNA and express viral transforming antigens, sT and tLT, but the role of these putative oncogenes in MCC development, and this tumor's cell of origin, are unknown. Using a panel of preterm transgenic mice, we show that epidermis-targeted coexpression of sT and the cell fate-determinant atonal bHLH transcription factor 1 (ATOH1) leads to development of widespread cellular aggregates, with histology and marker expression mimicking that of human intraepidermal MCC. The MCC-like tumor phenotype was dependent on the FBXW7-binding domain of sT, but not the sT-PP2A binding domain. Coexpression of MCPyV tLT did not appreciably alter the phenotype driven by either sT or sT combined with ATOH1. MCPyV sT, when coexpressed with ATOH1, is thus sufficient to initiate development of epidermis-derived MCC-like tumors in mice. Cancer Res; 77(12); 3151-7. ©2017 AACR.

Recurrence of Merkel cell carcinoma in the gastrointestinal tract: a case report

BACKGROUND

Merkel cell carcinoma is a rare and aggressive skin malignancy that arises from primary neural cells and has a tendency for local recurrence and regional lymph node metastases. There are only a few cases in the literature reporting metastases of Merkel cell carcinoma to the gastrointestinal tract.

CASE PRESENTATION

We present a 70 year old Caucasian female with distant history of Merkel cell carcinoma who presented with iron-deficiency anemia. Colonoscopy performed later for the evaluation of anemia revealed 1 cm polyp in ascending colon which turned out to be the recurrence of Merkel cell carcinoma.

CONCLUSION

Metastatic Merkel cell carcinoma to the gastrointestinal tract or any other organ should be considered in patients with a history of Merkel cell carcinoma.

Merkel Cell Carcinoma with a Suppressor of Fused (SUFU) Mutation: Case Report and Potential Therapeutic Implications

Introduction

Merkel cell carcinoma is a neuroendocrine malignancy. Suppressor of fused (SUFU) is a tumor suppressor oncogene that participates in the Hedgehog (Hh) signaling pathway. The aim of the study was to describe a patient whose Merkel cell carcinoma demonstrated a SUFU genomic alteration.

Case Study

The Hh signaling pathway is involved in the pathogenesis of several tumors, including nevoid basal cell carcinoma syndrome that is associated with an alteration of the patched-1 (PTCH1) gene. Targeted molecular therapy against smoothened (SMO) with vismodegib has been shown to be an effective therapeutic intervention for patients with PTCH-1 mutation. The reported patient was presented with metastatic Merkel cell carcinoma. Analysis of his tumor, using a next-generation sequencing-based assay, demonstrated a genomic aberration of SUFU protein, a component of the Hh signaling pathway that acts downstream to SMO and, therefore, is unlikely to be responsive to vismodegib. Of interest, arsenic trioxide or bromo and extra C-terminal inhibitors impact signals downstream to SUFU, making this aberration conceivably druggable. His tumor has initially been managed with chemotherapy (carboplatin and etoposide) and subsequent radiation therapy is planned.

Conclusion

The pathogenesis of Merkel cell carcinoma is multifactorial, and related to ultraviolet radiation exposure, immunosuppression, and Merkel cell polyomavirus. We report a patient with a mutation in SUFU, a potentially actionable component of the Hh signaling pathway.

Electronic supplementary material

The online version of this article (doi:10.1007/s13555-015-0074-5) contains supplementary material, which is available to authorized users.

Identification of geographic clustering and regions spared by cutaneous T-cell lymphoma in Texas using 2 distinct cancer registries

BACKGROUND

Cutaneous T-cell lymphomas (CTCLs) (mycosis fungoides and its leukemic variant, Sezary syndrome) are rare malignancies. Reports of the occurrence of mycosis fungoides in married couples and families raise the possibility of an environmental trigger for this cancer. Although it has been suggested that CTCL arises from inappropriate T-cell stimulation, to the authors' knowledge no preventable trigger has been identified to date.

METHODS

Using region, zip code, age, sex, and ethnicity, the authors analyzed the demographic data of 1047 patients from Texas who were seen in a CTCL clinic at The University of Texas MD Anderson Cancer Center during 2000 through 2012 (the MDACC database) and 1990 patients who were recorded in the population-based Texas Cancer Registry between 1996 and 2010. Subsequently, data from both databases were cross-analyzed and compared.

RESULTS

The current study findings, based on the MDACC database, documented geographic clustering of patients in 3 communities within the Houston metropolitan area, in which CTCL incidence rates were 5 to 20 times higher than the expected population rate. Analysis of the Texas Cancer Registry database defined the CTCL population rate for the state to be 5.8 cases per million individuals per year (95% confidence interval, 5.5-6.0 per million individuals per year), thus confirming the observations from the MDACC database and further highlighting additional areas of geographic clustering and regions spared from CTCL in Texas.

CONCLUSIONS

The current study documented geographic clustering of CTCL cases in Texas and argued for the existence of yet unknown external causes/triggers for this rare malignancy.

Gastric metastasis of Merkel cell carcinoma, a rare cause of gastrointestinal bleeding: case report and review of the literature

Merkel cell carcinoma (MCC) is a highly aggressive cutaneous tumor of neuroendocrine origin. It is usually seen in elderly Caucasian males and occurs in sun exposed areas of the body. Diagnosis of MCC can be challenging and requires confirmation by immunohistochemical studies. It has an aggressive biological behavior with early local and distant metastasis and carries a dismal prognosis. However, metastasis of MCC to the stomach is very uncommon and rarely reported in the literature. We hereby describe a patient with gastric metastasis of MCC, who presented with upper gastrointestinal (GI) bleeding.