Human polyomaviruses 6 and 7 are not detectable in Merkel cell polyomavirus-negative Merkel cell carcinoma

Background: Merkel cell carcinoma (MCC) has a high degree of association with Merkel cell polyomavirus (MCPyV). However, no reliable microscopic, clinical, phenotypic or molecular differences have been identified that distinguish MCPyV‐positive from MCPyV‐negative MCC, raising the possibility that a related polyomavirus may be present in MCPyV‐negative cases. Recently, two additional human polyomaviruses, human polyomaviruses 6 and 7 (HPyV6 and HPyV7), were shown to be present in normal skin of healthy subjects along with MCPyV. Consequently, we sought to determine if the presence of HPyV6 of HPyV7 could account for MCPyV‐negative MCC. Methods: DNA was extracted from formalin‐fixed, paraffin‐embedded tissue blocks of 28 previously characterized MCC cases that included 22 MCPyV‐positive and 6 MCPyV‐negative samples. Real‐time polymerase chain reaction targeting three viral regions was used to detect HPyV6 and HPyV7. Results: None of the 28 MCC cases, which included both MCPyV‐positive and negative cases, showed amplifiable HPyV6 or HPyV7 DNA. Conclusions: While MCPyV, HPyV6, and HPyV7 are part of normal skin flora and show a high degree of sequence similarity, there is no evidence of an association between HPyV6 and HPyV7 and MCC in this case series. This result argues against a role for HPyV6 and HPyV7 in the pathogenesis of MCPyV‐negative MCC. Duncavage EJ, Pfeifer JD. Human polyomaviruses 6 and 7 are not detectable in Merkel cell polyomavirus‐negative Merkel cell carcinoma.     

Usefulness of ulceration and hyperkeratosis as clinical predictors of Merkel cell polyomavirus‐negative and combined Merkel cell carcinoma: A retrospective study

Merkel cell carcinoma is a rare neuroendocrine carcinoma of the skin that is associated with Merkel cell polyomavirus (MCPyV). The clinical appearance and demographic characteristics of this tumor have been described using the mnemonic AEIOU: asymptomatic, expanding rapidly, immune suppression, older than 50 years, and ultraviolet‐exposed fair skin. In addition, MCC can be categorized based on morphology as pure MCC or combined MCC that exhibits neuroendocrine and other phenotypic elements. There is limited information regarding the clinical characteristics and prognosis of combined MCC. This retrospective study aimed to identify factors, such as ulceration or hyperkeratosis, that could predict MCPyV status and morphological variants. Twenty patients with MCC were divided into groups based on MCPyV status and morphology: MCPyV‐positive or MCPyV‐negative MCC and pure or combined MCC. The patients’ MCPyV status was immunohistochemically determined using the CM2B4 antibody to the MCPyV large T‐antigen. The patients’ clinicopathological characteristics were evaluated to identify predictors of MCPyV‐negative MCC and combined MCC. The presence of ulceration/hyperkeratosis predicted the presence of MCPyV‐negative MCC (80% of cases) and combined MCC (50% of cases). None of the 10 patients with MCPyV‐positive MCC had ulceration/hyperkeratosis. The clinical presence of ulceration/hyperkeratosis may help guide the diagnosis of MCPyV‐negative MCC and combined MCC.     

Merkel Cell Polyomavirus Is Frequently Detected in Korean Patients with Merkel Cell Carcinoma

Background

Merkel cell carcinoma (MCC) is an increasingly common neuroendocrine cancer of the skin. Merkel cell polyomavirus (MCPyV) is one of the causative agents of MCC. The prevalence of MCPyV in primary MCC and sun-exposed non-MCC tumors has been known to have different results depending on where it was investigated.

Objective

This study assesses the prevalence of MCPyV from primary MCC and sun-exposed non-MCC tumors in Korea.

Methods

A molecular pathology study was performed on 7 tissue specimens of MCC, 1 tissue specimen of metastatic small cell carcinoma of the lung, and 32 tissue specimens of non-MCC tumors occurring from sun-exposed areas [8 basal cell carcinomas (BCCs), 8 squamous cell carcinomas (SCCs), 8 actinic keratoses (AKs), and 8 seborrheic keratoses (SKs)]. All specimens were analyzed to determine the presence of MCPyV-DNA using both polymerase chain reaction (PCR) and real-time quantitative PCR. Immunohistochemistry with monoclonal antibody of MCPyV large T antigen (CM2B4) was also conducted.

Results

Using both PCR, MCPyV sequences were detected in six of seven MCC tissue specimens (85.7%). Five (71%) of seven MCC tumors were immunoreactive for CM2B4. All five immunoreactive cases were positive for MCPyV. However, there was no association of MCPyV with BCC, SCC, AK, and SK.

Conclusion

Our results implicate that MCPyV may contribute to the pathogenesis of primary MCC, not of non-MCC skin tumors in Korea, and the persons with MCPyV infection are unusual in Korea compared to other areas.     

Presence of the Merkel cell polyomavirus in Merkel cell carcinoma combined with squamous cell carcinoma in a patient with chronic arsenism

We present a case of Merkel cell carcinoma (MCC) coincident with squamous cell carcinoma (SCC) on the breast of a woman with chronic arsenism. This case demonstrates the distinct association of chronic arsenism with two different primary cutaneous carcinomas. Merkel cell polyomavirus (MCPyV) was identified in the lesional skin of the MCC but not in that of the SCC, suggesting there are different interactions of MCPyV in the pathogenesis of SCC and MCC related to arsenic. Physicians need to be vigilant in the occurrence of both SCC and MCC in patients with chronic arsenism. To our knowledge, this is the first study to show the presence of MCPyV in the MCC but not the SCC portion of an arsenic‐induced tumour.     

Merkel cell carcinoma with heterologous rhabdomyoblastic differentiation: the role of immunohistochemistry for Merkel cell polyomavirus large T-antigen in confirmation

Merkel cell carcinoma (MCC) represents an uncommon and lethal form of cutaneous malignancy. Historically, the pathogenesis of MCC has been presumed to be linked to ultraviolet light overexposure, but recently, it has been documented that some examples harbor polyomavirus genome, the presence of which is presumed to be of pathogenetic importance. Extremely rare cases of MCC may show heterologous differentiation. We report an example of MCC with heterologous rhabdomyosarcomatous differentiation, the third such case to date, with emphasis on its distinction from fusion-negative alveolar rhabdomyosarcoma. The role of immunohistochemistry for Merkel cell polyomavirus large T-antigen in this differential diagnosis is emphasized.     

Merkel细胞癌多瘤病毒阳性的皮肤原发性Merkel细胞癌二例

【摘要】 目的 报道Merkel细胞癌多瘤病毒阳性的Merkel细胞癌2例。 方法 对诊治的2例Merkel细胞癌进行光镜观察及免疫组化标记,聚合酶链反应（PCR）检测Merkel细胞癌多瘤病毒并测序。 结果 2例均为男性,例1右下肢胫前肿物1年余,皮肤科检查见右胫前密集粉红色结节,融合成10 cm × 8 cm肿块,质硬,部分表面糜烂伴渗出及结痂,肿块周围亦可见多个大小不一的红色结节,活动性差。例2左膝肿物6月余,皮肤科检查见左膝内侧5 cm × 4 cm紫蓝色结节型肿物,质硬,边界不清,活动性差。2例患者皮损组织病理表现相似,肿瘤细胞大小一致,细胞核大、深染,染色质细腻,核分裂象易见;胞质少,红染。免疫组化：广谱细胞角蛋白（pan-CK）、细胞角蛋白20（CK20）、突触素（Syn）、嗜铬素（CgA）和神经元特异性烯醇化酶（NSE）均阳性,Ki-67（≥60%）阳性;细胞角蛋白7（CK7）、S100蛋白、HMB45、CD34、甲状腺转录因子1（TTF-1）和白细胞共同抗原（LCA）表达均阴性。2例Merkel细胞癌均经PCR检测到Merkel细胞癌多瘤病毒,而5例皮肤T细胞淋巴瘤、2例正常人皮肤和2例T细胞淋巴瘤细胞系MAC1和MAC2A均未检测到Merkel细胞癌多瘤病毒。 结论 Merkel细胞癌具有特征性的临床和组织病理表现,免疫组化标记、PCR检测Merkel细胞癌多瘤病毒对明确诊断具有重要作用。 【关键词】 癌,Merkel细胞; 多瘤病毒属     

Merkel cell carcinoma associated with stable chronic hemodialysis: A report of two cases

Merkel cell carcinoma (MCC) is a rare but aggressive cutaneous malignancy associated with the Merkel cell polyomavirus (MCPyV). Multiple studies have shown that the incidence of MCC is higher among immunocompromised individuals than among the general population. In fact, immunosuppressed individuals account for approximately 10% of the MCC patient population. In this report, we describe two cases of MCPyV‐related MCC in Japanese patients on hemodialysis. In both the cases, MCC was present on the face. Both cellular and humoral immunities have been shown to be decreased in uremic patients, and dialysis patients have a high risk of viral‐mediated cancers, including human papillomavirus‐associated cancers. Immune dysfunction related to uremia and dialysis may be associated with a high risk of developing MCC.     

Ultrastructural studies of perichromatin granules with special references to Merkel cell carcinoma

Since it has been convincingly demonstrated that Merkel cell polyomavirus (MCPyV), a new type of virus, isolated in 2008, induces some of Merkel cell carcinoma (MCC), we searched MCPyV in specimens taken from MCC patients by electron microscopy. The purpose of this communication is to report the presence of perichromatin granules (PCGs), which can be misinterpreted as virus-like particles (VLP). Tissues from several cutaneous tumors including MCC were examined by electron microscopy (EM). EM revealed intranuclear and spherical electron-dense particles with halo, approximately 55 nm in diameter suggesting possible VLP. However, granular structures were detected in MCPyV DNA positive and also negative MCC. Moreover, the same structures were detected in the tumor cells of SCC associated with MCC, those of malignant melanoma (MM), schwannoma, and also in the lesional melanocyte, fibroblast, apoptotic cell and mitotic cell. Since MCPyV DNA could not be detected in collision MCC with SCC, MM and schwannoma, this observation could mean that the granular structures we dealt with in this report represent PCGs, but not VLP and show an absence of viral particles in MCC.     

Molecular pathogenesis of Merkel cell carcinoma

Abstract:  Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine skin cancer which is twice as lethal as melanoma as more than one-third of MCC patients will die from this cancer. Although MCC, which primarily affects elderly and immune suppressed individuals, is very rare to date, its incidence is rapidly increasing. In contrast to the immense progress that has been made in the elucidation of the molecular pathogenesis of other cancer entities, until recently there were no clear-cut indications which events drive the carcinogenesis of MCC. Important findings published last year have changed this radically. Hypermethylation of the p14^ARF promoter and a striking correlation between expression of p63 and the clinical course of MCC have been reported. Most important, however, is the discovery that MCC development in the majority of cases is preceded by the integration of genomic sequences of the hitherto unknown Merkel cell polyomavirus (MCPyV). Now a fundamental improvement in the understanding of MCC pathogenesis as well as the development of new therapeutic approaches based on this knowledge appear to be possible within the near future.     

Merkel细胞癌3例临床与病理分析

目的探讨Merkel细胞癌的临床与病理特点、病因学、诊断及鉴别诊断。方法观察3例Merkel细胞癌的组织病理特点和免疫组化染色结果,并复习相关文献。结果 3例均为老年患者,女2例,男1例。镜下见肿瘤主要位于真皮,呈巢索状和弥漫片状分布,癌细胞圆形、卵圆形或梭形,大小及形态较一致,胞质较少,核染色质细颗粒状,病理性核分裂像多见。免疫组化见CK20和神经内分泌标记阳性,HMB45,TTF-1,LCA和CD99等阴性。结论 Merkel细胞癌是一种发生于皮肤的少见的高度恶性神经内分泌肿瘤,易局部复发或转移。近年来发现的Merkel细胞多瘤病毒可能是其重要的致病因子。其临床病理及特征性的免疫组化表达有助于诊断及鉴别诊断。目前的治疗方法主要有手术切除和辅助放疗及化疗。     

Patched 1 expression in Merkel cell carcinoma

The relevance of Hedgehog signaling in Merkel cell carcinoma has only been addressed by a few studies with conflicting results. Thus, we aimed to establish the expression of Hedgehog signaling molecules in Merkel cell carcinoma to characterize causes of aberrant expression and to correlate these findings with the clinical course of the patients. Immunohistochemistry was performed for Sonic, Indian, Patched 1 (PTCH1) and Smoothened on patients’ tumor tissue. Respective mRNA expression was analyzed in 10 Merkel cell carcinoma cell lines using quantitative real‐time polymerase chain reaction. PTCH1 sequencing and DNA methylation microarray analyses were carried out on tumor tissues as well as cell lines. PTCH1 immunoreactivity in Merkel cell carcinoma was similar to that of basal cell carcinomas, which both significantly differed from PTCH1 immunoreactivity in healthy skin. Most PTCH1 mutations found were synonymous or without known functional impact. However, on average, the promoter regions of both PTCH1 were hypomethylated independently from PTCH1 gene expression or Merkel cell polyomavirus status. PTCH1 and GLI1/2/3 genes were differently expressed in different cell lines; notably, there was a significant correlation between GLI2 and PTCH1 mRNA expression. Similar to PTCH1 protein expression in patient tissues, PTCH1 gene expression in Merkel cell carcinoma cell lines is highly variable, but due to the similar methylation pattern across Merkel cell carcinoma cell lines, effects other than methylation seem to be the reason for the differential expression and PTCH1 appears to be upregulated by GLI as a classical Hedgehog target gene.     

An unusual case of diffuse Merkel cell carcinoma successfully treated with low dose radiotherapy

Merkel cell carcinoma (MCC) is a rare and highly aggressive neuroendocrine carcinoma of the skin. MCC should be included in the diagnosis of a rapidly growing infiltrating mass and histology as well as laboratory investigations such as Merkel cell polyoma virus (MCPyV) detection are valuable in its diagnosis. We present an unusual case of giant MCC‐positive MCPyV in a Greek woman located on the lower leg. Our patient is very unusual in terms of her extensive MCC and her rapid and complete response to radiotherapy.     

Prevalence and viral DNA loads of three novel human polyomaviruses in skin cancers from Japanese patients

Merkel cell polyomavirus (MCPyV), human polyomaviruses 6 (HPyV6) and 7 (HPyV7) are novel human polyomaviruses. This study investigated their detection rates and DNA loads in various skin cancers from Japanese patients. MCPyV, HPyV6 and HPyV7 were detected in 22.2%, 3.2% and 1.6% of squamous cell carcinomas, 18.0%, 2.0% and 4.0% of basal cell carcinomas, and 19.1%, 4.3% and 4.3% of melanomas, respectively. Quantitative real‐time polymerase chain reaction showed that their DNA loads were low. These findings provide the first evidence of the prevalence of HPyV6 and HPyV7 in skin cancers in Asia. Nucleotide differences were found in the large T‐sequenced region between Japanese and North American isolates: a nucleotide substitution of A to G for HPyV6; and a nucleotide substitution of T to C and the insertion of a gap for HPyV7. This suggested that two genotypes of HPyV6 and HPyV7 would be present and associated with geographical origin.     

病毒与皮肤肿瘤的相关性研究进展

病毒与皮肤肿瘤的关系得到越来越多的关注,病毒及相关皮肤肿瘤的研究中以人乳头瘤病毒、EB病毒、梅克尔细胞多瘤病毒、人免疫缺陷病毒等的研究最为广泛.有较多证据表明,人乳头瘤病毒与皮肤非黑素瘤肿瘤相关,EB病毒与皮肤淋巴瘤相关,梅克尔细胞多瘤病毒与梅克尔细胞癌相关,人免疫缺陷病毒与包括卡波西肉瘤在内的多种皮肤肿瘤相关.目前的研究认为,皮肤肿瘤是多种因素共同作用的最终结果,单一的病毒感染并非充分条件,病毒感染也不是肿瘤发生的必要因素.病毒与皮肤肿瘤的关系、病毒的致癌机制、病毒与其他因素之间如何共同作用以及病毒之间的相互作用,尚待研究阐明.     

Merkel cell carcinoma: epidemiology,clinical features,diagnosis and treatment of a rare disease

Merkel cell carcinoma is a rare skin cancer with neuroendocrine differentiation. The risk factors include sun exposure, advanced age, immunosuppression (such as transplant recipients, patients with lymphoproliferative neoplasms, or patients with HIV), and Merkel cell polyomavirus infection. Clinically, Merkel cell carcinoma appears as a cutaneous or subcutaneous plaque or nodule, but this tumor diagnosis is rarely made clinically. Therefore, histopathology and immunohistochemistry are usually necessary. Primary tumors without evidence of metastases are treated with complete surgical excision and appropriate surgical margins. The presence of occult metastasis in a lymph node is frequent and a sentinel lymph node biopsy should be performed. Postoperative adjuvant radiotherapy increases local tumor control. Recently, agents that block the PD-1/PD-L1 pathway have shown objective and durable tumor regression in patients with advanced solid malignancies. The first anti-PD-L1 antibody used in patients with Merkel cell carcinoma was avelumab, but pembrolizumab and nivolumab have also shown efficacy. This article describes the current state of knowledge of the epidemiology, diagnosis, and staging of Merkel cell carcinoma, as well as new strategies for its systemic treatment.     

Prevalence of MCPyV in Merkel cell carcinoma and non-MCC tumors

Background: Merkel cell polyomavirus (MCPyV) is the likely causative agent of Merkel cell carcinoma (MCC). However, the prevalence of MCPyV in non-MCC population and its possible role in the pathogenesis of other skin cancers are not known yet.
Methods: A molecular pathology study was performed in 33 MCC samples and 33 age- and sex-matched samples of sun exposed non-MCC tumors [12 seborrheic keratoses (SK), 11 basal cell carcinomas (BCC) and 10 lentigo maligna melanomas (LMM)]. All tumors were analyzed for presence of MCPyV-DNA by polymerase chain reaction (PCR) and Southern-Blot hybridization of PCR products.
Results: MCPyV sequences were detected in 21 MCC samples (64%) and in 2 non-MCC tumors of sun exposed skin (6%; both SK-patients). Neither the tissue samples from BCC nor LMM proved positive for MCPyV sequences.
Conclusion: We were able to confirm prior data on prevalence of MCPyV-DNA in MCC. Furthermore, a female predominance of MCPyV-positive MCC-patients was detected. There was no relevant association of MCPyV with SK, BCC and LMM. Speculative, prevalence of MCPyV in an age- and sex-matched non-MCC population could average up to 6%.