Home > Cancer Types > Skin Cancer > Merkel Cell Carcinoma

Merkel Cell Carcinoma

Merkel cell cancer (also known as trabecular cancer, or neuroendocrine cancer of the skin) is a rare type of malignancy developing on or just beneath the skin. These tumours can develop at any age, but the peak incidence is between ages 60 - 80. They are more frequent in white people, the most common sites of diseases are the face or scalp and other areas of high sun exposure. The Merkel cell polyomavirus (MCPyV), identified in humans in 2008, is suspected to have a role in the cause of most, but not all, cases of MCC.

Found this page useful?

Information for Patients and the Public
Information for Health Professionals / Researchers
Latest Research Publications
Skin Cancer

Information Patients and the Public (5 links)

Information for Health Professionals / Researchers (7 links)

  • PubMed search for publications about Merkel Cell Carcinoma - Limit search to: [Reviews]

    PubMed Central search for free-access publications about Merkel Cell Carcinoma
    MeSH term: Carcinoma, Merkel Cell
    International US National Library of Medicine
    qualityPubMed has over 22 million citations for biomedical literature from MEDLINE, life science journals, and online books. Constantly updated.

Latest Research Publications

This list of publications is regularly updated (Source: PubMed).

Gambichler T, Wieland U, Silling S, et al.
Left-sided laterality of Merkel cell carcinoma in a German population: more than just sun exposure.
J Cancer Res Clin Oncol. 2017; 143(2):347-350 [PubMed] Related Publications
BACKGROUND: Lateral distribution of cancer has been observed previously. Most evident is this laterality in ultraviolet (UV)-induced skin cancer, based on an unequally distributed UV exposure.
OBJECTIVES: The aim of this study was to explore whether patients from Germany also show asymmetrical lateral distribution of Merkel cell carcinoma (MCC).
METHODS: In total, 115 patients with MCC were studied for laterality of the primary tumour. Correlation of clinical variables with lateral distribution of MCC was investigated as well.
RESULTS: In 64/115 (55.7%) patients, primary tumours were present on the left side, in 37/115 (32.2%) on the right side, and in 14/115 (12.2%) in the midline (P < 0.0001). Excluding the latter localization occurrence of left-sided MCCs (64 of 101/63.4%) was significantly (P = 0.0072) more often observed (1.73-fold) when compared to right-sided tumours (37 of 101/36.6%). The excess of left-sided tumours was found on the head with a left-right ratio of 1.8, trunk of 8, arm of 1.2, and leg of 1.8. There was no significant association between laterality and gender, age, MCPyV status, and anatomic localization of primary tumours including the occurrence in sun-exposed sites.
CONCLUSIONS: Occurrence of left-sided MCCs was significantly more often observed when compared to right-sided tumours. Laterality was not associated with tumour presentation at chronically ultraviolet-exposed sites. Hence, the reason for laterality in MCC remains obscure, but likely goes beyond UV exposure.

Ahmadi Moghaddam P, Cornejo KM, Hutchinson L, et al.
Complete Spontaneous Regression of Merkel Cell Carcinoma After Biopsy: A Case Report and Review of the Literature.
Am J Dermatopathol. 2016; 38(11):e154-e158 [PubMed] Related Publications
Merkel cell carcinoma (MCC) is a rare primary cutaneous neuroendocrine tumor that typically occurs on the head and neck of the elderly and follows an aggressive clinical course. Merkel cell polyomavirus (MCPyV) has been identified in up to 80% of cases and has been shown to participate in MCC tumorigenesis. Complete spontaneous regression of MCC has been rarely reported in the literature. We describe a case of a 79-year-old man that presented with a rapidly growing, 3-cm mass on the left jaw. An incisional biopsy revealed MCC. Additional health issues were discovered in the preoperative workup of this patient which delayed treatment. One month after the biopsy, the lesion showed clinical regression in the absence of treatment. Wide excision of the biopsy site with sentinel lymph node dissection revealed no evidence of MCC 2 months later. The tumor cells in the patient's biopsy specimen were negative for MCPyV by polymerase chain reaction and immunohistochemistry (CM2B4 antibody, Santa Cruz, CA). The exact mechanism for complete spontaneous regression in MCC is unknown. To our knowledge, only 2 previous studies evaluated the presence of MCPyV by polymerase chain reaction in MCC with spontaneous regression. Whether the presence or absence of MCPyV correlates with spontaneous regression warrants further investigation.

Bermo MS, Leung A, Behnia F
A Case of Nasal Merkel Cell Carcinoma Draining to a Buccinator Sentinel Lymph Node.
Clin Nucl Med. 2016; 41(11):e480-e481 [PubMed] Related Publications
A 73-year-old man diagnosed with Merkel cell carcinoma of the left nasal ala was referred for preoperative scintigraphic sentinel lymph node mapping. In three separate foci around the lesion, 0.2 mCi of Tc-sulfur colloid was intradermally administered. Planar images demonstrated accumulation of tracer midway between the nose and left ear. SPECT/CT images localized radiotracer uptake to the left buccinator/buccal space, consistent with a buccinator lymph node, which is an inconsistent part of the facial lymphatic drainage. This case illustrates the added value of SPECT/CT and 3D reconstruction in sentinel lymph node localization, particularly in the head and neck.

Gambichler T, Mohtezebsade S, Wieland U, et al.
Prognostic relevance of high atonal homolog-1 expression in Merkel cell carcinoma.
J Cancer Res Clin Oncol. 2017; 143(1):43-49 [PubMed] Related Publications
BACKGROUND: It has recently been reported that atonal homolog 1 (ATOH1) gene is down-regulated in Merkel cell carcinoma (MCC) and thus may represent a tumor suppressor gene.
OBJECTIVES: We aimed to test for ATOH1 gene mutations and expression levels in MCC tissues and cell lines.
METHODS: Genomic DNA isolation and amplification via PCR was successfully performed in 33 MCCs on formalin-fixed paraffin-embedded tissue and three MCC cell lines, followed by Sanger sequencing of the whole ATOH1 gene to detect genomic aberrations. ATOH1 mRNA levels were determined by RT-PCR. Immunohistochemistry of ATOH1 was performed to quantify protein expression in tumor samples and cell lines.
RESULTS: Neither in any of the 33 MCC tissue samples nor in the three cell lines ATOH1 mutations were present. ATOH1 was expressed in all lesions, albeit at different expression levels. Univariate analysis revealed that the total immunohistology score significantly correlated with the occurrence of tumor relapse (r = 0.57; P = 0.0008). This notion was confirmed in multivariate analysis suggesting that ATOH1 expression is a potential independent predictor for tumor relapse in MCC patients (P = 0.028). MCC-related death also correlated with ATOH1 expression (r = 0.4; P = 0.025); however, ATOH1 expression did not retain its predictive value in the regression model.
CONCLUSIONS: In contrast to anecdotal reports ATOH1 expression is not lost by genetic alterations in MCC. However, protein expression of ATOH1 is increased in advanced MCC indicating that ATOH1 is involved in MCC progression.

Yu KK, Dasanu CA
Rapidly Fatal Dissemination of Merkel Cell Carcinoma in a Patient Treated with Alemtuzumab for Chronic Lymphocytic Leukemia.
Conn Med. 2016 Jun-Jul; 80(6):353-8 [PubMed] Related Publications
Alemtuzumab is FDA-approved for the treatment of chronic lymphocytic leukemia (CLL). Nonetheless, its use for this indication has fallen out of favor due to serious concerns for infectious complications and increased risks of second malignancies from the profound and lasting immunosuppression. We report here in a patient with a rapidly progressive metastatic Merkel cell carcinoma (MCC) who was previously treated with alemtuzumab and fludarabine for CLL. He developed profound lymphopenia and hypogammaglobulinemia. While the risk of MCC is increased in CLL, its rapid dissemination has not been previously reported with fludarabine alone. In light of the rapidly fatal outcome in our patient due to MCC, we advise caution with the use of alemtuzumab. In patients treated with alemtuzumab for nononcologic indications, aggressive surveillance for cutaneous malignancies should be implemented until its safety profile can be further characterized.

Husein-ElAhmed H, Ramos-Pleguezuelos F, Ruiz-Molina I, et al.
Histological Features, p53, c-Kit, and Poliomavirus Status and Impact on Survival in Merkel Cell Carcinoma Patients.
Am J Dermatopathol. 2016; 38(8):571-9 [PubMed] Related Publications
BACKGROUND: Merkel cell carcinoma (MCC) is a rare and aggressive malignancy from neuroendocrine cells in the skin. Despite being one of the most life-threatening of skin cancers, little is known about the potential signaling mechanism that drives carcinogenesis in MCC. The purpose of this study is to assess the impact of Merkel cell polyomavirus (MCPyV), p53, and c-kit on the histological features and clinical prognosis of MCC treated in our regional hospitals.
METHOD: The design was a retrospective study. The specimens were taken between 1993 and 2013 in 2 referral hospitals of Southern Spain. Data were collected retrospectively and analyzed using SPSS software.
RESULTS: Thirteen lesions from 13 subjects were included in the study. Positivity for c-kit was associated with the absence of MCPyV viral DNA (P = 0.048) and positivity for p53 (P = 0.002). More rate of mitoses per high-power field was presented significantly in those specimens with: positivity for c-kit (P = 0.046), positivity for p53 (P = 0.05), lesions with infiltrative growth pattern (P = 0.008), and lymphovascular invasion (P = 0.034). We observed an inverse relationship between p53 expression and MCPyV infection (Pearson's coefficient: -0.524; P = 0.046) and between c-kit expression and MCPyV infection (Pearson's coefficient: -0.548; P = 0.05), whereas the relationship was positive between p53 expression and c-kit expression (Pearson's coefficient: 0.884; P < 0.001).
CONCLUSION: We conclude that presence of MCPyV DNA has no effect on overall survival. MCCs with p53 and c-kit expressions are associated with the absence of or low MCPyV DNA showing an inverse relationship. A multifactorial molecular pathogenesis where positivity for p53 and c-kit are associated with other mechanisms different than MCPyV (such as pro-mitotic factors) may lead to aggressive clinical behavior.

Beckervordersandforth J, Pujari S, Rennspiess D, et al.
Frequent detection of human polyomavirus 6 in keratoacanthomas.
Diagn Pathol. 2016; 11(1):58 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: The recent discovery of the Merkel cell polyomavirus and its consistent association with Merkel cell carcinoma has drawn attention to the numerous recently discovered polyomaviruses and their possible involvement in the etiopathogenesis of non-melanoma skin cancer (NMSC). Data on the recently discovered human polyomavirus 6 (HPyV6) and its role in NMSC are sparse and in part controversial.
METHODS: In the present study we tested a large number (n = 299) of NMSC specimens for the presence of human polyomavirus 6 (HPyV6) by DNA PCR and HPyV6 fluorescence in situ hybridization (FISH). In detail, 59 keratoacanthomas (KA), 109 basal cell carcinomas (BCC), 86 squamous cell carcinomas (SCC) and 45 trichoblastomas (TB) were tested for the presence of HPyV6.
RESULTS: HPyV6 DNA PCR and subsequent sequence analysis revealed that 25 KAs (42.3 %), 23 BCCs (21.1 %), 8 SCCs (9.3 %) and 10 TBs (22.2 %) were HPyV6 positive. The presence of HPyV6 DNA was visualized and validated on the single cell level within the histomorphological context by HPyV6 fluorescence in situ hybridization.
CONCLUSIONS: The high frequency of HPyV6 DNA in 42.3 % of KA possibly points to a role for HPyV6 in the etiopathogenesis of KAs. Although the detection rate of HPyV6 DNA in BCCs and TBs is within the previously reported detection range in normal skin, it does not exclude a possible role for HPyV6 in the carcinogenesis in a significant subset of these skin tumors.

Czapiewski P, Majewska H, Kutzner H, et al.
TTF-1 and PAX5 Are Frequently Expressed in Combined Merkel Cell Carcinoma.
Am J Dermatopathol. 2016; 38(7):513-6 [PubMed] Related Publications
Thyroid transcription factor-1 (TTF-1) is a marker of tumors of pulmonary and thyroid origin, and its expression practically excludes diagnosis of Merkel cell carcinoma (MCC). However, TTF-1 expression in combined MCC was recently reported. PAX5 is a marker of B-cell origin that is also expressed in most classical MCC cases; however, its expression was not described in combined MCC. The authors decided to evaluate the expression of both these markers in a group of 5 combined MCCs (2 with invasive squamous cell carcinoma, 2 with squamous cell carcinoma in situ, and 1 with basal cell carcinoma). Expression of TTF-1 was found in 4 of 5 cases; in 3 cases, the marker was shown in the MCC component (weakly in 2 cases and strongly in 1 case), whereas the non-MCC component presented TTF-1 expression in 2 cases. A weak-to-moderate immunoreactivity for PAX5 was identified in all cases of the MCC component but in none of the non-MCC component. The results show that the expression of TTF-1 is a frequent finding in combined MCC and can be present in the neuroendocrine component, which differs from the conventional MCC. In contrast, PAX5 expression pattern is similar to that of the classical MCC.

Fukuhara M, Agnarsdóttir M, Edqvist PH, et al.
SATB2 is expressed in Merkel cell carcinoma.
Arch Dermatol Res. 2016; 308(6):449-54 [PubMed] Related Publications
Merkel cell carcinoma (MCC) is a rare aggressive skin cancer with neuroendocrine differentiation. With immunohistochemistry, the tumor cells stain for both neuroendocrine (i.e., synaptophysin and chromogranin A) and epithelial markers. The epithelial marker cytokeratin 20 (CK20) stains positive with immunohistochemistry in a vast majority of MCCs. The expression of the special AT-rich sequence-binding protein (SATB2) was analyzed in MCC (n = 20) together with other forms of skin cancer and neuroendocrine tumors (n = 51) using immunohistochemistry. The results were compared to the expression of CK20, synaptophysin, and chromogranin A. The majority of the MCCs stained positive for synaptophysin and chromogranin A (95 vs 80 % respectively), and 75 % of the MCCs showed cytoplasmic positivity for CK20 and nuclear positivity for SATB2, with two discordant cases lacking expression of one of these markers. We conclude that immunohistochemistry for SATB2 can be used as an additional marker with similar sensitivity and specificity as CK20 for the diagnosis of Merkel cell carcinoma, suggesting a clinical utility in difficult cases where MCC is suspected.

Thiels CA, Gonzalez AB, Gray RJ, Jakub JW
Isolated limb perfusion in Merkel cell carcinoma offers high rate of complete response and durable local-regional control: Systematic review and institutional experience.
J Surg Oncol. 2016; 114(2):187-92 [PubMed] Related Publications
INTRODUCTION: Hyperthermic isolated limb perfusion (HILP) has an established role in the management of melanoma, but its role for Merkel cell carcinoma (MCC) is less well defined.
METHODS: Retrospective review of our institutional experience with HILP for MCC was conducted (2009-2015). Literature search was performed through 04/2015 and 10 studies met inclusion criteria.
RESULTS: Four patients underwent HILP for MCC at our institution. There were no major complications and complete response was achieved in all patients. Early metastatic recurrence developed in two patients. The remaining two had no evidence of disease at last follow-up (36 months) or death (39 months). Systematic review identified an additional 12 pts that underwent HILP for MCC, for a total of 16 cases. Median age was 73 [IQR 69-78] years and 56% were men. Of the patients with reported follow-up, 12 (86%) had complete response, 1 had stable disease, and 1 partial response. Four patients developed local-regional recurrence and six distant metastases, all within 6 months. Overall median follow-up time was 15 [7-36] months.
CONCLUSION: Among a highly selective group of patients, regional perfusion for MCC is safe and has a high complete response rate. HILP is an acceptable therapeutic modality for obtaining durable loco-regional control but early distant metastatic disease remains a significant cause of mortality. J. Surg. Oncol. 2016;114:187-192. © 2016 Wiley Periodicals, Inc.

Nghiem PT, Bhatia S, Lipson EJ, et al.
PD-1 Blockade with Pembrolizumab in Advanced Merkel-Cell Carcinoma.
N Engl J Med. 2016; 374(26):2542-52 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Merkel-cell carcinoma is an aggressive skin cancer that is linked to exposure to ultraviolet light and the Merkel-cell polyomavirus (MCPyV). Advanced Merkel-cell carcinoma often responds to chemotherapy, but responses are transient. Blocking the programmed death 1 (PD-1) immune inhibitory pathway is of interest, because these tumors often express PD-L1, and MCPyV-specific T cells express PD-1.
METHODS: In this multicenter, phase 2, noncontrolled study, we assigned adults with advanced Merkel-cell carcinoma who had received no previous systemic therapy to receive pembrolizumab (anti-PD-1) at a dose of 2 mg per kilogram of body weight every 3 weeks. The primary end point was the objective response rate according to Response Evaluation Criteria in Solid Tumors, version 1.1. Efficacy was correlated with tumor viral status, as assessed by serologic and immunohistochemical testing.
RESULTS: A total of 26 patients received at least one dose of pembrolizumab. The objective response rate among the 25 patients with at least one evaluation during treatment was 56% (95% confidence interval [CI], 35 to 76); 4 patients had a complete response, and 10 had a partial response. With a median follow-up of 33 weeks (range, 7 to 53), relapses occurred in 2 of the 14 patients who had had a response (14%). The response duration ranged from at least 2.2 months to at least 9.7 months. The rate of progression-free survival at 6 months was 67% (95% CI, 49 to 86). A total of 17 of the 26 patients (65%) had virus-positive tumors. The response rate was 62% among patients with MCPyV-positive tumors (10 of 16 patients) and 44% among those with virus-negative tumors (4 of 9 patients). Drug-related grade 3 or 4 adverse events occurred in 15% of the patients.
CONCLUSIONS: In this study, first-line therapy with pembrolizumab in patients with advanced Merkel-cell carcinoma was associated with an objective response rate of 56%. Responses were observed in patients with virus-positive tumors and those with virus-negative tumors. (Funded by the National Cancer Institute and Merck; ClinicalTrials.gov number, NCT02267603.).

Ben-Haim S, Garkaby J, Primashvili N, et al.
Metabolic assessment of Merkel cell carcinoma: the role of 18F-FDG PET/CT.
Nucl Med Commun. 2016; 37(8):865-73 [PubMed] Related Publications
OBJECTIVES: Merkel cell carcinoma (MCC) is a rare aggressive skin tumor associated with a high mortality rate. The present study evaluated the role of fluorine-18 fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) in subsequent management of patients with MCC.
METHODS: A total of 101 consecutive F-FDG PET/CT studies of 46 patients with MCC (28 men, 68±15.4 years) were retrospectively evaluated and the role in clinical care was documented.
RESULTS: There were 40 positive studies (40%) in 28 patients (61%); of these, 33 studies (33%) in 27 patients (59%) showed metastatic disease. Fifty-two PET/CT studies (51%) in 23/46 (50%) patients were negative. Fifty-three studies (52%) were performed for staging or restaging in 41 patients, 29 scans (29%) were performed for routine follow-up in 10 patients, nine studies were carried out for suspected recurrent disease in eight patients, and 10 studies were carried out for assessment of response to therapy in seven patients. On the basis of PET/CT results, there was a change in disease stage in 12 studies in 12 patients (26%) and further change in the management of seven patients (15%). Overall, 2/29 routine follow-up studies were positive with further impact on management in one patient.
CONCLUSION: F-FDG PET-CT altered the stage of one of four patients and changed the management of one of seven MCC patients. In the majority of patients, a negative F-FDG PET-CT study excluded active MCC with a high degree of confidence. PET-CT contributed toward patient management when performed for staging and restaging, monitoring response to treatment, and suspected recurrent disease, but not in the routine follow-up of asymptomatic patients with MCC.

van den Berg NS, Engelen T, Brouwer OR, et al.
A pilot study of SPECT/CT-based mixed-reality navigation towards the sentinel node in patients with melanoma or Merkel cell carcinoma of a lower extremity.
Nucl Med Commun. 2016; 37(8):812-7 [PubMed] Related Publications
OBJECTIVE: To explore the feasibility of an intraoperative navigation technology based on preoperatively acquired single photon emission computed tomography combined with computed tomography (SPECT/CT) images during sentinel node (SN) biopsy in patients with melanoma or Merkel cell carcinoma.
MATERIALS AND METHODS: Patients with a melanoma (n=4) or Merkel cell carcinoma (n=1) of a lower extremity scheduled for wide re-excision of the primary lesion site and SN biopsy were studied. Following a Tc-nanocolloid injection and lymphoscintigraphy, SPECT/CT images were acquired with a reference target (ReTp) fixed on the leg or the iliac spine. Intraoperatively, a sterile ReTp was placed at the same site to enable SPECT/CT-based mixed-reality navigation of a gamma ray detection probe also containing a reference target (ReTgp).The accuracy of the navigation procedure was determined in the coronal plane (x, y-axis) by measuring the discrepancy between standard gamma probe-based SN localization and mixed-reality-based navigation to the SN. To determine the depth accuracy (z-axis), the depth estimation provided by the navigation system was compared to the skin surface-to-node distance measured in the computed tomography component of the SPECT/CT images.
RESULTS: In four of five patients, it was possible to navigate towards the preoperatively defined SN. The average navigational error was 8.0 mm in the sagittal direction and 8.5 mm in the coronal direction. Intraoperative sterile ReTp positioning and tissue movement during surgery exerted a distinct influence on the accuracy of navigation.
CONCLUSION: Intraoperative navigation during melanoma or Merkel cell carcinoma surgery is feasible and can provide the surgeon with an interactive 3D roadmap towards the SN or SNs in the groin. However, further technical optimization of the modality is required before this technology can become routine practice.

Hashimoto K, Yasumatsu R, Toh S, et al.
Patterns of lymphatic spread and the management of eyelid carcinomas.
Auris Nasus Larynx. 2016; 43(6):666-71 [PubMed] Related Publications
OBJECTIVE: Eyelid carcinomas are rare, and the management strategy of regional lymph node metastasis linked to eyelid carcinomas has not been standardized to date. The aim of the present study was to analyze the patterns of regional metastasis and to assess the optimal extent of surgical treatment for lymph node metastasis of eyelid carcinoma.
METHODS: This study was a retrospective review of patient data from a single institution. From a series of 268 eyelid carcinomas, we selected the 21 patients with lymph node metastasis, and we analyzed the patterns of lymphatic spread, approach to treatment and outcomes.
RESULTS: The most common histological type of eyelid carcinoma with regional metastasis was sebaceous carcinoma (17/21, 81.0%). Submandibular area metastases were seen only in the patients with the primary tumor originating in the medial half of the eyelid, but parotid area metastases were seen in both the patients whose tumors had a medial-half origin and those with a lateral-half origin. Although 11 of the 16 patients with parotid-area metastases underwent a tumorectomy or superficial parotidectomy (which resulted in four cases of recurrence in the parotid area), none of the five patients who underwent a total parotidectomy developed parotid-area recurrence. The incidence of regional recurrence of the patients who received adjuvant radiotherapy (14.3%) was lower than that of the patients without adjuvant radiotherapy (57.1%).
CONCLUSION: Continued surveillance and optimal management of regional lymph node metastases are important for the control and survival of eyelid carcinomas.

Ritter C, Fan K, Paulson KG, et al.
Reversal of epigenetic silencing of MHC class I chain-related protein A and B improves immune recognition of Merkel cell carcinoma.
Sci Rep. 2016; 6:21678 [PubMed] Free Access to Full Article Related Publications
Merkel cell carcinoma (MCC) is a virally associated cancer characterized by its aggressive behavior and strong immunogenicity. Both viral infection and malignant transformation induce expression of MHC class I chain-related protein (MIC) A and B, which signal stress to cells of the immune system via Natural Killer group 2D (NKG2D) resulting in elimination of target cells. However, despite transformation and the continued presence of virally-encoded proteins, MICs are only expressed in a minority of MCC tumors in situ and are completely absent on MCC cell lines in vitro. This lack of MIC expression was due to epigenetic silencing via MIC promoter hypo-acetylation; indeed, MIC expression was re-induced by pharmacological inhibition of histone deacetylases (HDACs) both in vitro and in vivo. This re-induction of MICs rendered MCC cells more sensitive to immune-mediated lysis. Thus, epigenetic silencing of MICs is an important immune escape mechanism of MCCs.

Abraham KJ, Zhang X, Vidal R, et al.
Roles for miR-375 in Neuroendocrine Differentiation and Tumor Suppression via Notch Pathway Suppression in Merkel Cell Carcinoma.
Am J Pathol. 2016; 186(4):1025-35 [PubMed] Related Publications
Dysfunction of key miRNA pathways regulating basic cellular processes is a common driver of many cancers. However, the biological roles and/or clinical applications of such pathways in Merkel cell carcinoma (MCC), a rare but lethal cutaneous neuroendocrine (NE) malignancy, have yet to be determined. Previous work has established that miR-375 is highly expressed in MCC tumors, but its biological role in MCC remains unknown. Herein, we show that elevated miR-375 expression is a specific feature of well-differentiated MCC cell lines that express NE markers. In contrast, miR-375 is strikingly down-regulated in highly aggressive, undifferentiated MCC cell lines. Enforced miR-375 expression in these cells induced NE differentiation, and opposed cancer cell viability, migration, invasion, and survival, pointing to tumor-suppressive roles for miR-375. Mechanistically, miR-375-driven phenotypes were caused by the direct post-transcriptional repression of multiple Notch pathway proteins (Notch2 and RBPJ) linked to cancer and regulation of cell fate. Thus, we detail a novel molecular axis linking tumor-suppressive miR-375 and Notch with NE differentiation and cancer cell behavior in MCC. Our findings identify miR-375 as a putative regulator of NE differentiation, provide insight into the cell of origin of MCC, and suggest that miR-375 silencing may promote aggressive cancer cell behavior through Notch disinhibition.

Morand GB, Madana J, Da Silva SD, et al.
Merkel cell carcinoma of the head and neck: poorer prognosis than non-head and neck sites.
J Laryngol Otol. 2016; 130(4):393-7 [PubMed] Related Publications
BACKGROUND: Merkel cell carcinoma is a rare, aggressive neurocutaneous malignancy. This study investigated whether patients with Merkel cell carcinoma in the head and neck had poorer outcomes than patients with Merkel cell carcinoma located elsewhere.
METHODS: A retrospective study was performed of patients with Merkel cell carcinoma treated at the Jewish General Hospital in Montréal, Canada, from 1993 to 2013. Associations between clinicopathological characteristics and disease-free and disease-specific survival rates were examined according to the Kaplan-Meier method.
RESULTS: Twenty-seven patients were identified. Although basic clinicopathological characteristics and treatments were similar between head and neck and non-head and neck Merkel cell carcinoma groups, disease-free and disease-specific survival rates were significantly lower in the head and neck Merkel cell carcinoma group (log-rank test; p = 0.043 and p = 0.001, respectively). Mortality was mainly due to distant metastasis.
CONCLUSION: Patients with head and neck Merkel cell carcinoma had poorer survival rates than patients with non-head and neck Merkel cell carcinoma in our study. The tendency to obtain close margins, a less predictable metastatic pattern, and/or intrinsic tumour factors related to the head and neck may explain this discrepancy.

Taghizadeh Kermani A, Rezaei E, Zarifmahmoudi L, Sadeghi R
Lymphatic mapping and sentinel node biopsy in a patient with upper limb Merkel Cell Carcinoma: a case report and brief review of literature.
Nucl Med Rev Cent East Eur. 2016; 19(1):42-5 [PubMed] Related Publications
Sentinel node mapping is an integral part of regional lymph node staging in many solid tumors and plays an important role in surgical oncology. This technique has been used with excellent results for non-melanoma skin cancers including Merkel Cell Carcinoma (MCC). In the current study, we reported our first MCC patient who underwent successful sentinel node mapping. We also reviewed the available literature regarding the prognostic significance of sentinel node mapping in cN0 MCC patients.

Haag T, Richter AM, Schneider MB, et al.
The dual specificity phosphatase 2 gene is hypermethylated in human cancer and regulated by epigenetic mechanisms.
BMC Cancer. 2016; 16:49 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Dual specificity phosphatases are a class of tumor-associated proteins involved in the negative regulation of the MAP kinase pathway. Downregulation of the dual specificity phosphatase 2 (DUSP2) has been reported in cancer. Epigenetic silencing of tumor suppressor genes by abnormal promoter methylation is a frequent mechanism in oncogenesis. It has been shown that the epigenetic factor CTCF is involved in the regulation of tumor suppressor genes.
METHODS: We analyzed the promoter hypermethylation of DUSP2 in human cancer, including primary Merkel cell carcinoma by bisulfite restriction analysis and pyrosequencing. Moreover we analyzed the impact of a DNA methyltransferase inhibitor (5-Aza-dC) and CTCF on the epigenetic regulation of DUSP2 by qRT-PCR, promoter assay, chromatin immuno-precipitation and methylation analysis.
RESULTS: Here we report a significant tumor-specific hypermethylation of DUSP2 in primary Merkel cell carcinoma (p = 0.05). An increase in methylation of DUSP2 was also found in 17 out of 24 (71%) cancer cell lines, including skin and lung cancer. Treatment of cancer cells with 5-Aza-dC induced DUSP2 expression by its promoter demethylation, Additionally we observed that CTCF induces DUSP2 expression in cell lines that exhibit silencing of DUSP2. This reactivation was accompanied by increased CTCF binding and demethylation of the DUSP2 promoter.
CONCLUSIONS: Our data show that aberrant epigenetic inactivation of DUSP2 occurs in carcinogenesis and that CTCF is involved in the epigenetic regulation of DUSP2 expression.

Kleffel S, Lee N, Lezcano C, et al.
ABCB5-Targeted Chemoresistance Reversal Inhibits Merkel Cell Carcinoma Growth.
J Invest Dermatol. 2016; 136(4):838-46 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine skin cancer with profound but poorly understood resistance to chemotherapy, which poses a significant barrier to clinical MCC treatment. Here we show that ATP-binding cassette member B5 (ABCB5) confers resistance to standard-of-care MCC chemotherapeutic agents and provide proof-of-principle that ABCB5 blockade can inhibit human MCC tumor growth through sensitization to drug-induced cell cytotoxicity. ABCB5 expression was detected in both established MCC lines and clinical MCC specimens at levels significantly higher than those in normal skin. Carboplatin- and etoposide-resistant MCC cell lines exhibited increased expression of ABCB5, along with enhanced ABCB1 and ABCC3 transcript expression. ABCB5-expressing MCC cells in heterogeneous cancers preferentially survived treatment with carboplatin and etoposide in vitro and in human MCC xenograft-bearing mice in vivo. Moreover, patients with MCC also exhibited enhanced ABCB5 positivity after carboplatin- and etoposide-based chemotherapy, pointing to clinical significance of this chemoresistance mechanism. Importantly, ABCB5 blockade reversed MCC drug resistance and impaired tumor growth in xenotransplantation models in vivo. Our results establish ABCB5 as a chemoresistance mechanism in MCC and suggest utility of this molecular target for improved MCC therapy.

Zwald F, Leitenberger J, Zeitouni N, et al.
Recommendations for Solid Organ Transplantation for Transplant Candidates With a Pretransplant Diagnosis of Cutaneous Squamous Cell Carcinoma, Merkel Cell Carcinoma and Melanoma: A Consensus Opinion From the International Transplant Skin Cancer Collaborative (ITSCC).
Am J Transplant. 2016; 16(2):407-13 [PubMed] Related Publications
Advancements in solid organ transplantation successfully extend the lives of thousands of patients annually. The tenet of organ stewardship aims to prevent the futile expenditure of scarce donor organs in patient populations with high mortality risk, to the detriment of potential recipients with greater predicted life expectancy. The development of skin cancer posttransplantation portends tremendous morbidity, adversely affecting quality of life for many transplant recipients. This special article, provided by of members of the International Transplant Skin Cancer Collaborative (ITSCC), will provide the transplant professional with a consensus opinion and recommendations as to an appropriate wait period pretransplantation for transplant candidates with a history of either cutaneous squamous cell carcinoma, malignant melanoma, or Merkel cell carcinoma.

Mauzo SH, Ferrarotto R, Bell D, et al.
Molecular characteristics and potential therapeutic targets in Merkel cell carcinoma.
J Clin Pathol. 2016; 69(5):382-90 [PubMed] Related Publications
Merkel cell carcinoma (MCC) is an aggressive neuroendocrine skin tumour occurring preferentially in elderly and immunosuppressed individuals. Multiple studies have provided insight into the molecular alterations of MCC, leading to the design of several ongoing clinical trials testing chemotherapy, targeted therapy and immunotherapy in patients with recurrent or metastatic disease. The results of some of these studies are available, whereas others are eagerly awaited and will likely shed light on the understanding of MCC biology and potentially improve the clinical outcomes of patients with this rare disease.

Wu JH, Simonette RA, Nguyen HP, et al.
Emerging differential roles of the pRb tumor suppressor in trichodysplasia spinulosa-associated polyomavirus and Merkel cell polyomavirus pathogeneses.
J Clin Virol. 2016; 76:40-3 [PubMed] Related Publications
BACKGROUND: Merkel cell carcinoma (MCC) and trichodysplasia spinulosa (TS) are two proliferative cutaneous diseases caused by the Merkel cell polyomavirus (MCPyV) and trichodysplasia spinulosa-associated polyomavirus (TSPyV) respectively. Recently, studies have elucidated a key role of the small tumor (sT) antigen in the proliferative pathogenic mechanisms of MCPyV and likely TSPyV. While both sT antigens have demonstrated a capacity in regulating cellular pathways, it remains unknown whether MCPyV and TSPyV sT antigens contribute similarly or differentially to cell proliferation.
OBJECTIVES: The present study aims to explore the proliferative potential of MCPyV and TSPyV sT antigens by investigating their regulatory effects on the retinoblastoma protein (pRb) tumor suppressor.
STUDY DESIGN: Inducible cell lines expressing MCPyV sT or TSPyV sT were created using a lentiviral packaging system. Cellular proteins were extracted and subjected to SDS-PAGE followed by Western blot detection and densitometric analysis.
RESULTS: Expression of TSPyV sT markedly enhanced the phosphorylation of pRb in Western blot experiments. In contrast, expression of MCPyV sT did not alter pRb phosphorylation under the same experimental conditions. Densitometric analysis revealed that TSPyV sT antigen expression nearly doubled the ratio of phosphorylated to total pRb (P<0.001, Student's T-test), while MCPyV sT antigen expression did not cause significant change in pRb phosphorylation status.
CONCLUSION: Given that hyperphosphorylation of pRb is associated with dysregulation of the cell cycle, S-phase induction, and increased cell proliferation, our findings support an important role of TSPyV-mediated pRb deactivation in the development of TS. The observation that the pRb tumor suppressor is inactivated by TSPyV sT but not MCPyV sT provides further insights into the distinct pathobiological mechanisms of MCC and TS.

Iwasaki T, Matsushita M, Nonaka D, et al.
Lower expression of CADM1 and higher expression of MAL in Merkel cell carcinomas are associated with Merkel cell polyomavirus infection and better prognosis.
Hum Pathol. 2016; 48:1-8 [PubMed] Related Publications
Merkel cell carcinoma (MCC) is a clinically aggressive neuroendocrine skin cancer; 80% of the cases are associated with the Merkel cell polyomavirus (MCPyV). We previously reported that MCPyV-negative MCCs have more irregular nuclei with abundant cytoplasm and significantly unfavorable outcomes than do MCPyV-positive MCCs. These results suggest that some cell adhesion or structural stabilization molecules are differently expressed depending on MCPyV infection status. Thus, we investigated the association of prognosis or MCPyV infection status in MCCs with cell adhesion molecule 1 (CADM1)/differentially expressed in adenocarcinoma of the lung protein 1 (DAL-1)/membrane protein, palmitoylated 3 (MPP3) tripartite complex and mal T-cell differentiation protein (MAL) expression, which play important roles in cell adhesion and oncogenesis and are related to cancer outcomes in various malignancies, to elucidate the role of these molecules. We analyzed the pathological and molecular characteristics of 26 MCPyV-positive and 15 MCPyV-negative MCCs. Univariate Cox regression analysis showed that advanced age (hazard ratio [HR], 8.249; P = .007) and high CADM1 expression (HR, 5.214; P = .012) were significantly unfavorable overall survival parameters, whereas MCPyV infection (HR, 0.043, P < .001) and lower MAL expression (HR, 0.273; P = .018) were significantly favorable. On multivariate analysis, only MCPyV infection was significantly favorable for overall survival (HR, 0.04; P = .005). Hypermethylation of CADM1, DAL-1, and MAL promoters was detected in 1 of 18, 15 of 27, and 1 of 13 cases, respectively. Double immunostaining for cytokeratin 20 and CADM1, DAL-1, or MAL showed that nonneoplastic Merkel cells expressed DAL-1 and MAL but not CADM1. This study revealed that MCPyV-negative MCCs significantly expressed higher CADM1 and lower MAL than MCPyV-positive MCCs; these expression levels were markedly related to unfavorable outcomes. These data will give us important insights to develop novel molecular target therapies for MCCs.

Harms PW, Collie AM, Hovelson DH, et al.
Next generation sequencing of Cytokeratin 20-negative Merkel cell carcinoma reveals ultraviolet-signature mutations and recurrent TP53 and RB1 inactivation.
Mod Pathol. 2016; 29(3):240-8 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Merkel cell carcinoma is a rare but highly aggressive cutaneous neuroendocrine carcinoma. Cytokeratin 20 (CK20) is expressed in ~95% of Merkel cell carcinomas and is useful for distinction from morphologically similar entities including metastatic small-cell lung carcinoma. Lack of CK20 expression may make diagnosis of Merkel cell carcinoma more challenging, and has unknown biological significance. Approximately 80% of CK20-positive Merkel cell carcinomas are associated with the oncogenic Merkel cell polyomavirus. Merkel cell carcinomas lacking Merkel cell polyomavirus display distinct genetic changes from Merkel cell polyomavirus-positive Merkel cell carcinoma, including RB1 inactivating mutations. Unlike CK20-positive Merkel cell carcinoma, the majority of CK20-negative Merkel cell carcinomas are Merkel cell polyomavirus-negative, suggesting CK20-negative Merkel cell carcinomas predominantly arise through virus-independent pathway(s) and may harbor additional genetic differences from conventional Merkel cell carcinoma. Hence, we analyzed 15 CK20-negative Merkel cell carcinoma tumors (10 Merkel cell polyomavirus-negative, four Merkel cell polyomavirus-positive, and one undetermined) using the Ion Ampliseq Comprehensive Cancer Panel, which assesses copy number alterations and mutations in 409 cancer-relevant genes. Twelve tumors displayed prioritized high-level chromosomal gains or losses (average 1.9 per tumor). Non-synonymous high-confidence somatic mutations were detected in 14 tumors (average 11.9 per tumor). Assessing all somatic coding mutations, an ultraviolet-signature mutational profile was present, and more prevalent in Merkel cell polyomavirus-negative tumors. Recurrent deleterious tumor suppressor mutations affected TP53 (9/15, 60%), RB1 (3/15, 20%), and BAP1 (2/15, 13%). Oncogenic activating mutations included PIK3CA (3/15, 20%), AKT1 (1/15, 7%) and EZH2 (1/15, 7%). In conclusion, CK20-negative Merkel cell carcinoma display overlapping genetic changes with CK20-positive Merkel cell carcinoma, including RB1 mutations restricted to Merkel cell polyomavirus-negative tumors. However, some CK20-negative Merkel cell carcinomas harbor mutations not previously described in Merkel cell carcinoma. Hence, CK20-negative Merkel cell carcinomas harbor diverse oncogenic drivers which may represent therapeutic targets in individual tumors.

Veija T, Sarhadi VK, Koljonen V, et al.
Hotspot mutations in polyomavirus positive and negative Merkel cell carcinomas.
Cancer Genet. 2016 Jan-Feb; 209(1-2):30-5 [PubMed] Related Publications
Merkel cell polyomavirus (MCV) infection underlies most Merkel cell carcinoma (MCC), a primary neuroendocrine carcinoma of the skin. While previous research has focused on MCV-positive MCC tumors, less is known about the oncogenesis in MCV-negative tumors. In this study, we analyzed mutational status of 27 MCC tumors with known MCV status for hotspot regions of 50 cancer-related genes by targeted next-generation sequencing using the Ion AmpliSeq Cancer Hotspot Panel. In addition to previously reported TP53, KIT, and PIK3CA gene mutations, we found somatic mutations in the tyrosine kinase domain of the EGFR gene in a small proportion of the cells in six tumor tissues. RB1 mutations were seen only in virus negative tumors. Hotspot mutations were more frequent in MCV-negative tumors, although the difference was not statistically significant. No clear hotspot mutation profile was observed. Novel RB1 mutations were detected only in MCV-negative tumors.

Miles BA, Goldenberg D,
Merkel cell carcinoma: Do you know your guidelines?
Head Neck. 2016; 38(5):647-52 [PubMed] Related Publications
BACKGROUND: Merkel cell carcinoma (MCC) is a cutaneous neuroendocrine malignancy that exhibits clinically aggressive features and is associated with a poor prognosis. The incidence of MCC seems to be increasing for reasons unknown, and is estimated to be 0.32/100,000 in the United States.
METHODS: This article will review the current literature and National Comprehensive Cancer Network practice guidelines in the treatment of MCC.
RESULTS: Resection of MCC with negative margins remains the mainstay of therapy. Positive nodal disease should be treated with neck dissection and adjuvant radiotherapy. High-risk patients should undergo adjuvant radiotherapy, which improves oncologic outcomes. The role of chemotherapy is less clear and is currently reserved for advanced-stage MCC and palliative therapy.
CONCLUSION: The pathogenesis of MCC has recently been impacted with the discovery of the Merkel cell polyomavirus (MCPyV). Research to establish targeted and immunologic therapeutic options are ongoing.

Cestaro G, Festa P, Cricrì AM, et al.
Unexpected histopathologic result of a wide surgical excision of a bleeding lesion of the skin: a case of Merkel cell carcinoma of the leg.
G Chir. 2015 Sep-Oct; 36(5):231-5 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
BACKGROUND: Merkel cell Carcinoma is a very rare primary cutaneous tumor that often looks like an innocuous and asymptomatic nodule or plaque of the skin, but with a very fast growing. It is also called neuroendocrine carcinoma of the skin or trabecular cancer. The main treatment is based on a local excision followed by radiotherapy or chemotherapy. The most common site of presentation of this lesion is head and neck (40-60%.) and it often occur in older men with immunological system dysfunction like HIV patients, cancer, severe infections and immunosuppression for transplantation.
METHODS: The authors report a case of a bleeding Merkel Cell Carcinoma of the right leg in a 83 years old man with HCV infection, chronic kidney disease and diabetes mellitus type 2 that required local excision.
RESULTS: Lesion was entirely removed and then patient was sent to oncologists. After two months from surgical excision, healing process is regular and without complications.
CONCLUSIONS: This type of tumor can be misdiagnosed and, if bleeding, it can represent a serious surgical emergency.

Goh G, Walradt T, Markarov V, et al.
Mutational landscape of MCPyV-positive and MCPyV-negative Merkel cell carcinomas with implications for immunotherapy.
Oncotarget. 2016; 7(3):3403-15 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Merkel cell carcinoma (MCC) is a rare but highly aggressive cutaneous neuroendocrine carcinoma, associated with the Merkel cell polyomavirus (MCPyV) in 80% of cases. To define the genetic basis of MCCs, we performed exome sequencing of 49 MCCs. We show that MCPyV-negative MCCs have a high mutation burden (median of 1121 somatic single nucleotide variants (SSNVs) per-exome with frequent mutations in RB1 and TP53 and additional damaging mutations in genes in the chromatin modification (ASXL1, MLL2, and MLL3), JNK (MAP3K1 and TRAF7), and DNA-damage pathways (ATM, MSH2, and BRCA1). In contrast, MCPyV-positive MCCs harbor few SSNVs (median of 12.5 SSNVs/tumor) with none in the genes listed above. In both subgroups, there are rare cancer-promoting mutations predicted to activate the PI3K pathway (HRAS, KRAS, PIK3CA, PTEN, and TSC1) and to inactivate the Notch pathway (Notch1 and Notch2). TP53 mutations appear to be clinically relevant in virus-negative MCCs as 37% of these tumors harbor potentially targetable gain-of-function mutations in TP53 at p.R248 and p.P278. Moreover, TP53 mutational status predicts death in early stage MCC (5-year survival in TP53 mutant vs wild-type stage I and II MCCs is 20% vs. 92%, respectively; P = 0.0036). Lastly, we identified the tumor neoantigens in MCPyV-negative and MCPyV-positive MCCs. We found that virus-negative MCCs harbor more tumor neoantigens than melanomas or non-small cell lung cancers (median of 173, 65, and 111 neoantigens/sample, respectively), two cancers for which immune checkpoint blockade can produce durable clinical responses. Collectively, these data support the use of immunotherapies for virus-negative MCCs.

Wong SQ, Waldeck K, Vergara IA, et al.
UV-Associated Mutations Underlie the Etiology of MCV-Negative Merkel Cell Carcinomas.
Cancer Res. 2015; 75(24):5228-34 [PubMed] Related Publications
Merkel cell carcinoma (MCC) is an uncommon, but highly malignant, cutaneous tumor. Merkel cell polyoma virus (MCV) has been implicated in a majority of MCC tumors; however, viral-negative tumors have been reported to be more prevalent in some geographic regions subject to high sun exposure. While the impact of MCV and viral T-antigens on MCC development has been extensively investigated, little is known about the etiology of viral-negative tumors. We performed targeted capture and massively parallel DNA sequencing of 619 cancer genes to compare the gene mutations and copy number alterations in MCV-positive (n = 13) and -negative (n = 21) MCC tumors and cell lines. We found that MCV-positive tumors displayed very low mutation rates, but MCV-negative tumors exhibited a high mutation burden associated with a UV-induced DNA damage signature. All viral-negative tumors harbored mutations in RB1, TP53, and a high frequency of mutations in NOTCH1 and FAT1. Additional mutated or amplified cancer genes of potential clinical importance included PI3K (PIK3CA, AKT1, PIK3CG) and MAPK (HRAS, NF1) pathway members and the receptor tyrosine kinase FGFR2. Furthermore, looking ahead to potential therapeutic strategies encompassing immune checkpoint inhibitors such as anti-PD-L1, we also assessed the status of T-cell-infiltrating lymphocytes (TIL) and PD-L1 in MCC tumors. A subset of viral-negative tumors exhibited high TILs and PD-L1 expression, corresponding with the higher mutation load within these cancers. Taken together, this study provides new insights into the underlying biology of viral-negative MCC and paves the road for further investigation into new treatment opportunities.

Disclaimer: This site is for educational purposes only; it can not be used in diagnosis or treatment.

[Home]    Page last updated: 07 March, 2017     © CancerIndex, Established 1996