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.     

Case of Merkel cell carcinoma with squamous cell carcinoma possibly arising in chronic radiodermatitis of the hand

We report a case of Merkel cell carcinoma (MCC) on the dorsal aspect of the right middle finger associated with multiple squamous cell carcinomas (SCC) possibly arising in chronic radiation dermatitis of the hand of an 80‐year‐old surgeon. In spite of resection of the primary lesion and right axillary lymph nodes, he died of the tumor 5 months after the first visit. Cutaneous and lymph node lesions of MCC were negative for Merkel cell polyoma virus (MCPyV) by immunostaining using monoclonal antibody (CM2B4) and anti‐large T antigen of MCPyV polyclonal antibody, and real‐time polymerase chain reaction. Several differences in clinicopathological findings have been found between MCPyV‐positive cases and negative ones. Several authors have reported that MCPyV‐negative cases have a worse prognosis than MCPyV‐positive ones. Furthermore, in cases of MCC associated with SCC, most tumors have been reported to be MCPyV‐negative. We should pay more attention to the relationship between the carcinogenesis of MCC and ionizing irradiation.     

Immunohistochemical prognostication of Merkel cell carcinoma: p63 expression but not polyomavirus status correlates with outcome

Merkel cell carcinoma (MCC) represents a cutaneous malignancy with high associated mortality. Numerous studies have attempted to define characteristics to more accurately predict outcome. Two recent studies have demonstrated that Merkel cell polyomavirus (MCPyV) seropositivity correlated with a better prognosis, while a third study revealed no difference. Expression of p63 by tumor cell nuclei has been shown to be associated with a worse prognosis in a European cohort. To better understand the relationship between prognosis and MCPyV or p63 status, we used immunohistochemistry to evaluate both attributes in 36 US patients with MCC. Our results show that when considered as a binary variable, p63 expression represents a strong risk factor (p < 0.0001, hazards ratio (HR) = ∞) for shortened survival. In addition, our results show that MCPyV status does not correlate with survival (p = 0.6067, HR = 1.27). Our study corroborates the European observation that p63 immunoexpression is useful as a prognostic tool. Larger studies will need to be performed in order to determine whether p63 status should be included in MCC staging, since our study is limited by its relative small size.     

Identification of Merkel cell polyomavirus in Merkel cell carcinoma tissue: case report of a Taiwanese patient

Merkel cell carcinoma (MCC) is a rare malignancy with aggressive behavior mostly seen in the elderly and immunosuppressed patients. In 2008, the clonal integration of a new human polyomavirus, named Merkel cell polyomavirus (MCPyV), was found to be closely associated with the development of MCC. This correlation was established by subsequent reports, mostly in Caucasians. To evaluate whether this correlation is also relevant among the Taiwanese population, we used polymerase chain reaction to detect the presence of MCPyV in a formalin-fixed and paraffin-embedded MCC specimen. In addition, we used tissue with seborrheic keratosis from the same patient as a control. Three different specific primer sets, LT1, LT3 and VP1, were used to amplify characteristic MCPyV genes, and large T antigen and VP1 genes, respectively. Amplicons of the expected sizes for all three primer pairs were detected in MCC tissue and amplicons for both LT3 and VP1 were detected in seborrheic keratosis tissue. More studies are needed to quantify viral positivity of MCPyV in various tissues of patients with MCC and to establish genetic interactions between the virus and host.     

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 polyomavirus DNA detection in lesional and nonlesional skin from patients with Merkel cell carcinoma or other skin diseases

Summary Background A novel polyomavirus, the Merkel cell polyomavirus (MCPyV), has recently been identified in Merkel cell carcinoma (MCC). Objectives To investigate the specificity of this association through the detection, quantification and analysis of MCPyV DNA in lesional and nonlesional skin biopsies from patients with MCC or with other cutaneous diseases, as well as in normal skin from clinically healthy individuals. Methods DNA was extracted from lesional and nonlesional skin samples of patients with MCC or with other cutaneous diseases and from normal‐appearing skin of clinically healthy subjects. MCPyV DNA was detected by polymerase chain reaction (PCR) and quantified by real‐time PCR. Additionally, the T antigen coding region was sequenced in eight samples from seven patients. Results MCPyV DNA was detected in 14 of 18 (78%) patients with MCC, five of 18 (28%) patients with other skin diseases (P = 0·007) and one of six (17%) clinically healthy subjects. In patients with MCC, viral DNA was detected in nine of 11 (82%) tumours and in 10 of 14 (71%) nontumoral skin samples (P = 0·66). MCPyV DNA levels were higher in MCC tumours than in nontumoral skin from patients with MCC, and than in lesional or nonlesional skin from patients with other cutaneous disorders. Signature mutations in the T antigen gene were not identified in the two MCC tumour specimens analysed. Conclusions High prevalence and higher levels of MCPyV DNA in MCC supports a role for MCPyV in tumorigenesis. However, the high prevalence of MCPyV in the nontumoral skin and in subjects without MCC suggests that MCPyV is a ubiquitous virus.     

Merkel cell carcinoma update: the case for two tumours

Merkel cell carcinoma (MCC) is an aggressive tumour with neuroendocrine differentiation. Clinically significant differences within the entity we know as MCC are apparent. This review aims to evaluate the evidence for differences in tumours within Merkel cell carcinoma and to stratify these. A literature search of research pertaining to various characteristics MCC was undertaken from 1972, when Merkel cell carcinoma was first described, to 2018, using PubMed and similar search engines. A total of 41 papers were analysed, including clinical trials, laboratory-based research and reviews. A proportion of MCC has Merkel cell polyomavirus genome integrated (MCPyV+) while others do not (MCPyV−). Both types have a different mutation burden. MCPyV+ tumours are likely true neuroendocrine carcinomas, with a dermal origin, probably from fibroblasts which have been transformed by integration of the viral genome. MCPyV−tumours are likely derived from either keratinocytes or epidermal stem cells, are probably squamous cell carcinomas with neuroendocrine differentiation, and are related to sun damage. Prognostic factors (apart from tumour stage) include the MCPyV status, with MCPyV+ tumours having a better prognosis. P63 expression confers a worse prognosis in most studies. CD8+ lymphocytes play an important role, providing a possible target for PD1/PD-L1 blockade treatment. The incidence of MCC varies from country to country. Countries such as Australia have a high rate and a far greater proportion of MCPyV− tumours than places such as the United Kingdom. MCC doubtlessly encompasses two tumours. The two tumours have demonstrated differences in prognosis and management. One is a neuroendocrine carcinoma related to MCPyV integration likely derived from fibroblasts, and the other is a UV-related squamous cell carcinoma with neuroendocrine differentiation, presumptively derived from either keratinocytes or epidermal stem cells. We propose naming the former Merkel type sarcoma and the latter squamous cell carcinoma, Merkel type.     

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%.     

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.     

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.     

Human polyomaviruses and cancer: expanding repertoire

Polyomaviruses were originally isolated in mouse and in monkey (SV40) about 50 years ago. In 1971, the first human polyomaviruses BK and JC were isolated and subsequently demonstrated to be ubiquitous in the human population. Recent studies have shown that SV40 can spread between humans and led to the identification of three new human polyomaviruses (KIPyV, MCPyV, and WUPyV). BKV, JCV, and SV40 appear harmless in healthy individuals, but possess pathogenic properties in immunosuppressed patients. Moreover they may play an etiological role in human malignancies. Epidemiologic and pathogenic studies of KIPyV, MCPyC, and WUPyV are limited so far, but MCPyV may be associated with Merkel cell carcinoma, a rare but aggressive neuroendocrine skin cancer. We describe the biology of human polyomaviruses, review their non‐malignant and malignant potentials, and discuss the mechanisms by which these viruses may contribute to transformation.     

A Systematic review and Meta-Analysis of the survival and clinicopathological features of p63 expression in Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare skin tumour of neuroendocrine origin with aggressive behaviour. The aims of this study were to investigate the association of p63 + MCC with clinicopathological features and to estimate survival through a systematic review and meta-analysis. A comprehensive search of PubMed, Embase, Scopus and Virtual Health Library following the PRISMA guidelines was conducted on September 2017. DerSimonian and Lard random-effects models were used to calculate survival-weighted means and their corresponding 95% confidence intervals (CI) among studies. Five studies met our inclusion criteria after screening 77 citations and 36 full-text articles. The included studies enrolled 413 patients with MCC. We observed that p63 + MCC was significantly associated with mortality with OR 2.92 (95% CI [1.66–5.13]). The summary hazard ratio of multivariate analysis was 1.99 (95% CI [1.32–3.01]). The only clinicopathological feature associated with p63 + MCC with statistical significance was the Merkel cell polyomavirus (MCPyV) status. The presence of MCPyV was associated as a protective factor for the expression of p63 (OR 0.25, 95% CI [0.08–0.73]). These results support that p63 + MCC evaluated by immunohistochemistry has a poor outcome. Therefore, we suggest p63 to be performed when staging 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.     

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 showing regression after biopsy: Evaluation of programmed cell death 1‐positive cells

We present a cases of Merkel cell carcinoma (MCC) with Merkel cell polyomavirus that showed complete regression after biopsy. The exact mechanism of regression in MCC has remained unclear. It has been reported that apoptosis caused by T‐cell immunity was implicated in the regression, and programmed cell death 1 (PD‐1), an inhibitory receptor, was expressed in approximately half of tumor‐infiltrating T cells in MCC. However, the contribution of PD‐1‐positive cells for the regression of MCC has not been evaluated. We examined the rate of PD‐1‐positive cells among the peritumoral mononuclear cells, which showed that the percentage of PD‐1‐positive cells in the case was significantly lower compared with in MCC without regression. We propose that PD‐1‐positive cells suppress tumor immunity for MCC, and that reduction of PD‐1‐positive cells may be associated with tumor regression.