Immunosuppression and Merkel cell cancer

Characterization of the Impact of Merkel Cell Polyomavirus-Induced Interferon Signaling on Viral Infection

Merkel cell polyomavirus (MCPyV) has been associated with approximately 80% of Merkel cell carcinoma (MCC), an aggressive and increasingly incident skin cancer. The link between host innate immunity, viral load control, and carcinogenesis has been established but poorly characterized. We previously established the importance of the STING and NF-κB pathways in the host innate immune response to viral infection. In this study, we further discovered that MCPyV infection of human dermal fibroblasts (HDFs) induces the expression of type I and III interferons (IFNs), which in turn stimulate robust expression of IFN-stimulated genes (ISGs). Blocking type I IFN downstream signaling using an IFN-β antibody, JAK inhibitors, and CRISPR knockout of the receptor dramatically repressed MCPyV infection-induced ISG expression but did not significantly restore viral replication activities. These findings suggest that IFN-mediated induction of ISGs in response to MCPyV infection is not crucial to viral control. Instead, we found that type I IFN exerts a more direct effect on MCPyV infection postentry by repressing early viral transcription. We further demonstrated that growth factors normally upregulated in wounded or UV-irradiated human skin can significantly stimulate MCPyV gene expression and replication. Together, these data suggest that in healthy individuals, host antiviral responses, such as IFN production induced by viral activity, may restrict viral propagation to reduce MCPyV burden. Meanwhile, growth factors induced by skin abrasion or UV irradiation may stimulate infected dermal fibroblasts to promote MCPyV propagation. A delicate balance of these mutually antagonizing factors provides a mechanism to support persistent MCPyV infection. IMPORTANCE Merkel cell carcinoma is an aggressive skin cancer that is particularly lethal to immunocompromised individuals. Though rare, MCC incidence has increased significantly in recent years. There are no lasting and effective treatments for metastatic disease, highlighting the need for additional treatment and prevention strategies. By investigating how the host innate immune system interfaces with Merkel cell polyomavirus, the etiological agent of most of these cancers, our studies identified key factors necessary for viral control, as well as conditions that support viral propagation. These studies provide new insights for understanding how the virus balances the effects of the host immune defenses and of growth factor stimulation to achieve persistent infection. Since virus-positive MCC requires the expression of viral oncogenes to survive, our observation that type I IFN can repress viral oncogene transcription indicates that these cytokines could be explored as a viable therapeutic option for treating patients with virus-positive MCC.

Merkel Cell Polyomavirus Infection Induces an Antiviral Innate Immune Response in Human Dermal Fibroblasts

Merkel cell polyomavirus (MCPyV) infects most of the human population asymptomatically, but in rare cases it leads to a highly aggressive skin cancer called Merkel cell carcinoma (MCC). MCC incidence is much higher in aging and immunocompromised populations. The epidemiology of MCC suggests that dysbiosis between the host immune response and the MCPyV infectious cycle could contribute to the development of MCPyV-associated MCC. Insufficient restriction of MCPyV by normal cellular processes, for example, could promote the incidental oncogenic MCPyV integration events and/or entry into the original cell of MCC. Progress toward understanding MCPyV biology has been hindered by its narrow cellular tropism. Our discovery that primary human dermal fibroblasts (HDFs) support MCPyV infection has made it possible to closely model cellular responses to different stages of the infectious cycle. The present study reveals that the onset of MCPyV replication and early gene expression induces an inflammatory cytokine and interferon-stimulated gene (ISG) response. The cGAS-STING pathway, in coordination with NF-κB, mediates induction of this innate immune gene expression program. Further, silencing of cGAS or NF-κB pathway factors led to elevated MCPyV replication. We also discovered that the PYHIN protein IFI16 localizes to MCPyV replication centers but does not contribute to the induction of ISGs. Instead, IFI16 upregulates inflammatory cytokines in response to MCPyV infection by an alternative mechanism. The work described herein establishes a foundation for exploring how changes to the skin microenvironment induced by aging or immunodeficiency might alter the fate of MCPyV and its host cell to encourage carcinogenesis. IMPORTANCE MCC has a high rate of mortality and an increasing incidence. Immune-checkpoint therapies have improved the prognosis of patients with metastatic MCC. Still, a significant proportion of the patients fail to respond to immune-checkpoint therapies or have a medical need for iatrogenic immune-suppression. A greater understanding of MCPyV biology could inform targeted therapies for MCPyV-associated MCC. Moreover, cellular events preceding MCC oncogenesis remain largely unknown. The present study aims to explore how MCPyV interfaces with innate immunity during its infectious cycle. We describe how MCPyV replication and/or transcription elicit an innate immune response via cGAS-STING, NF-κB, and IFI16. We also explore the effects of this response on MCPyV replication. Our findings illustrate how healthy cellular conditions may allow low-level infection that evades immune destruction until highly active replication is restricted by host responses. Conversely, pathological conditions could result in unbridled MCPyV replication that licenses MCC tumorigenesis.

Viruses and Skin Cancer

Advances in virology and skin cancer over recent decades have produced achievements that have been recognized not only in the field of dermatology, but also in other areas of medicine. They have modified the therapeutic and preventive solutions that can be offered to some patients and represent a significant step forward in our knowledge of the biology of skin cancer. In this paper, we review the viral agents responsible for different types of skin cancer, especially for solid skin tumors. We focus on human papillomavirus and squamous cell cancers, Merkel cell polyomavirus and Merkel cell carcinoma, and human herpesvirus 8 and Kaposi’s sarcoma.

Artesunate Affects T Antigen Expression and Survival of Virus-Positive Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a rare and highly aggressive skin cancer with frequent viral etiology. Indeed, in about 80% of cases, there is an association with Merkel cell polyomavirus (MCPyV); the expression of viral T antigens is crucial for growth of virus-positive tumor cells. Since artesunate—a drug used to treat malaria—has been reported to possess additional anti-tumor as well as anti-viral activity, we sought to evaluate pre-clinically the effect of artesunate on MCC. We found that artesunate repressed growth and survival of MCPyV-positive MCC cells in vitro. This effect was accompanied by reduced large T antigen (LT) expression. Notably, however, it was even more efficient than shRNA-mediated downregulation of LT expression. Interestingly, in one MCC cell line (WaGa), T antigen knockdown rendered cells less sensitive to artesunate, while for two other MCC cell lines, we could not substantiate such a relation. Mechanistically, artesunate predominantly induces ferroptosis in MCPyV-positive MCC cells since known ferroptosis-inhibitors like DFO, BAF-A1, Fer-1 and β-mercaptoethanol reduced artesunate-induced death. Finally, application of artesunate in xenotransplanted mice demonstrated that growth of established MCC tumors can be significantly suppressed in vivo. In conclusion, our results revealed a highly anti-proliferative effect of the approved and generally well-tolerated anti-malaria compound artesunate on MCPyV-positive MCC cells, suggesting its potential usage for MCC therapy.

Monoclonal Antibodies in Dermatooncology-State of the Art and Future Perspectives

Monoclonal antibodies (mAbs) targeting specific proteins are currently the most popular form of immunotherapy used in the treatment of cancer and other non-malignant diseases. Since the first approval of anti-CD20 mAb rituximab in 1997 for the treatment of B-cell malignancies, the market is continuously booming and the clinically used mAbs have undergone a remarkable evolution. Novel molecular targets are constantly emerging and the development of genetic engineering have facilitated the introduction of modified mAbs with improved safety and increased capabilities to activate the effector mechanisms of the immune system. Next to their remarkable success in hematooncology, mAbs have also an already established role in the treatment of solid malignancies. The recent development of mAbs targeting the immune checkpoints has opened new avenues for the use of this form of immunotherapy, also in the immune-rich milieu of the skin. In this review we aim at presenting a comprehensive view of mAbs' application in the modern treatment of skin cancer. We present the characteristics and efficacy of mAbs currently used in dermatooncology and summarize the recent clinical trials in the field. We discuss the side effects and strategies for their managing.

Seed and soil? - Pharyngeal Merkel cell carcinoma after radiotherapy for laryngeal squamous cell carcinoma

Merkel cell carcinoma (MCC) is a neuroendocrine cutaneous malignancy that may present as metastatic disease without a known primary site but, most commonly originates in the sun-exposed skin of the head, neck, and extremities. We present a 66-year-old male treated with chemo-radiation for T3N2cM0 laryngeal squamous cell carcinoma (SCCa) six years before he was diagnosed with MCC isolated to the radiated laryngopharynx. Mucosal MCC is rare and radiation-induced MCC has been hypothesized to occur in previously radiated tissue but, never before to the laryngopharynx. Implications regarding cancer biology and management is focused with discussion on relevant advances in pathologic assessment and immunotherapy.

Primary Merkel cell carcinoma of the earlobe in a young healthy man

Merkel cell carcinoma (MCC) is an uncommon neuroendocrine cutaneous tumor with poor prognosis. It has the high rate of recurrence, mortality, regional nodal involvement, and distant metastases. It is difficult to diagnose MCC because of its non-specific clinical findings. It usually occurs on sun-exposed areas of the skin, mostly at head and neck. There is a difference in the incidence and prognosis according to site in the head and neck. However, there is no consented site-specific diagnosis, treatment or follow-up protocol for MCC at the head and neck. We herein report a case of MCC arising in the right earlobe of an otherwise healthy young man who has been diagnosed early, thereby successfully treated. With our closed follow-up, there was no tumor recurrence or complication at 33 months after diagnosis.

Updates on the Management of Non-Melanoma Skin Cancer (NMSC)

Non-melanoma skin cancers (NMSCs) are the most common malignancy worldwide, of which 99% are basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) of skin. NMSCs are generally considered a curable diseases, yet they currently pose an increasing global healthcare problem due to rising incidence. This has led to a shift in emphasis on prevention of NMSCs with development of various skin cancer prevention programs worldwide. This article aims to summarize the most recent changes and advances made in NMSC management with a focus on prevention, screening, diagnosis, and staging.

Rationale for immune-based therapies in Merkel polyomavirus-positive and -negative Merkel cell carcinomas

Merkel cell carcinoma (MCC) is a rare but often deadly skin cancer that is typically caused by the Merkel cell polyomavirus (MCPyV). Polyomavirus T-antigen oncoproteins are persistently expressed in virus-positive MCCs (˜80% of cases), while remarkably high numbers of tumor-associated neoantigens are detected in virus-negative MCCs, suggesting that both MCC subsets may be immunogenic. Here we review mechanisms by which these immunogenic tumors evade multiple levels of host immunity. Additionally, we summarize the exciting potential of diverse immune-based approaches to treat MCC. In particular, agents blocking the PD-1 axis have yielded strikingly high response rates in MCC as compared with other solid tumors, highlighting the potential for immune-mediated treatment of this disease.

Comparison of the incidence of skin cancers in patients on dialysis and after kidney transplantation

INTRODUCTION

Kidney transplant (KTx) patients on immunosuppressive therapy are predisposed to the development of infections and cancers.

AIM

To compare the incidence and type of malignant skin lesions in kidney transplant patients and the dialyzed population based on the initiated dermatologic screening.

MATERIAL AND METHODS

The study included 598 patients: 486 kidney transplant recipients and 112 patients on maintenance dialysis. All the patients underwent dermatological examination. Only histologically confirmed cancers were included in this study. Age, gender and immunosuppressive therapy administration were also considered. Patients were followed up by a dermatologist for a period of 5 years.

RESULTS

Fifty-eight skin cancers; 39 basal cell carcinomas (BCC), 13 squamous cell carcinomas (SCC), 1 Bowen disease, 2 Kaposi sarcoma, 1 malignant melanoma, 1 Merkel cell carcinoma, and 1 fibrosarcoma protuberans were diagnosed in 30 (6.2%) kidney transplant patients, and 8 lesions (7 BCC and 1 SCC) were found in 4 (3.6%) patients on dialysis.

CONCLUSIONS

The initiated dermatologic screening program indicates that the risk of skin cancer incidence in post kidney transplant patients receiving immunosuppressive therapy was significantly higher than in patients on dialysis.

High-risk cutaneous malignancies and immunosuppression: Challenges for the reconstructive surgeon in the renal transplant population

Renal transplantation is the most frequently performed transplant procedure. Immunosuppressive therapies have dramatically increased survival rates in transplant recipients but are associated with an increased risk of skin cancers. Recent changes in immunosuppressive strategies have been adopted with the aim of reducing this challenging adverse effect. Despite these new strategies, cutaneous malignancies tend to be numerous, aggressive and associated with a higher risk of local and distant dissemination than in the non-transplant population. This represents a significant workload for transplant physicians, dermatologists, and head and neck and plastic surgeons. This review highlights key concepts in the pathogenesis of skin cancer in transplant patients, the impact current and evolving immunosuppressive strategies and regimens will have on the epidemiology, and the management of cutaneous malignancies in renal transplant patients, with particular focus on the implications for the plastic surgery community.

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)

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.

Molecular characteristics and potential therapeutic targets in Merkel cell carcinoma

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.

[Merkel cell carcinoma]

Merkel cell carcinoma (MCC, cutaneous neuroendocrine carcinoma) is a rare form of tumor of unclear histogenesis which predominantly occurs in elderly patients on areas exposed to the sun. A higher incidence and occurrence in younger people is predominantly found in immunosuppressed persons which is why a pathogenetic role is also attributed to immunosuppression in addition to ultraviolet (UV) radiation. Additionally, in 80% of cases clonally integrated polyomavirus (Merkel cell polyomavirus, MCPyV) could be detected. Clinically MCC represents an uncharacteristic tumor. Histopathologically, monomorphic dermal and/or subcutaneous nodes are found consisting of round or oval medium sized cells with a vesicular nucleus and sparse cytoplasm. The neoplastic cells of MCC express cytokeratin (CK) 20 with a dot-like perinuclear accentuation. In addition, pan-CK, neuroendocrine markers (e.g. chromogranin A and synaptophysin), neurofilament proteins, CD56, CD57, Bcl-2, TdT and PAX-5 are immunohistochemically positive. In most cases CM2B4, an antibody against MCPyV is also positive. Expression of p63 has been observed in some of the cases and in some studies was associated with a favorable prognosis. The markers thyroid transcription factor 1, mammalian achaete scute complex like 1, vimentin, S-100 and CK7 are not normally expressed by MCC. The prognosis is primarily dependent on tumor size and the lymph node status. The presence of intralymphatic tumor complexes is associated with a higher rate of local recurrence and lymph node metastasis. A larger number of intratumoral cytotoxic T-lymphocytes is accompanied by a favorable prognosis and the presence of > 50% of K-67+ neoplastic cells with an unfavorable prognosis. Further morphological, phenotypical and genetic factors have not yet been validated in larger cohorts with respect to the prognostic relevance.

Post-transplantation malignancies: here today, gone tomorrow?

From the early days of transplantation onwards, increased cancer development in transplant recipients, who require immunosuppression to avoid graft rejection, has been recognized. Registry data indicate that approximately 10-30% of deaths are attributed to post-transplant malignancy, with an upward trend in this incidence as more patients have been exposed to chronic lifelong immunosuppression. In this Review, the overall incidence and most frequent types of cancer encountered are summarized, along with information about which transplant recipients are at the greatest risk of malignancy. Reasons for why differences exist in susceptibility to cancer in this patient population are examined, and approaches that might improve our understanding of the options available for reducing the incidence of this adverse effect of immunosuppression are described. Whether anti-rejection drugs have been successful in diminishing overall immunosuppressive burden, and consequently show any promise for decreasing post-transplant malignancies is also discussed. The topic shifts to one class of conventional anti-rejection drugs, the mammalian target of rapamycin (mTOR) inhibitors, which paradoxically have both immunosuppressive and anti-neoplastic properties. The complex activities of mTOR are reviewed in order to provide context for how these seemingly opposing effects are possible, and the latest clinical data on use of mTOR inhibitors in the clinic are discussed. The current and future perspectives on how best to normalize these unacceptably high rates of post-transplantation malignancies are highlighted.

Skin Cancer in the Crosshairs: Highlights from the Biennial Scientific Retreat of International Transplant Skin Cancer Collaborative and Skin Care in Organ Transplant Recipients Europe

The International Transplant Skin Cancer Collaborative (ITSCC) is an organization comprising of physicians; transplant surgeons and basic science research scientists dedicated in providing optimal care and ongoing research advancements in solid organ transplant recipients to improve patient outcome and quality of life. As medical advances occur, it is anticipated that the sheer number of solid organ transplantations occurring worldwide will continue to increase. The long-term medication associated immunosuppression improves graft survival, but as a consequence, these individuals become increasingly susceptible to various cutaneous malignancies, lymphoproliferative disorders and infections. Squamous cell carcinoma is the most frequently encountered skin cancer and increases 65- to 250-fold [Jensen et al., Skin cancer in kidney and heart transplant recipients and different long-term immunosuppressive therapy regimens. J Am Acad Dermatol. 1999;40:177-186; Lindelöf et al., Incidence of skin cancer in 5356 patients following organ transplantation. Br J Dermatol. 2000; 143:513-519]. However, the rates of basal cell carcinoma, Merkel cell carcinoma and melanoma also increase in organ transplant recipients leading to significant morbidity as well as mortality [Berg and Otley. Skin cancer in organ transplant recipients: epidemiology, pathogenesis, and management. J Am Acad Dermatol. 2002; 47:1-20]. In October 2014, the International Transplant Skin Cancer Collaborative and its equivalent European counterpart, Skin Care in Organ Transplant Recipients Europe held its 10th biennial meeting in Essex, MA to discuss the clinical conundrums and the evolving research pertinent to the field. This meeting report provides a synthesis of all the clinical and research data presented at the 4-day meeting.

Joint occurrence of Merkel cell carcinoma and non-Hodgkin lymphomas in four Nordic countries

The objective of this study was to assess the reciprocal association between non-Hodgkin lymphoma (NHL) and Merkel cell carcinoma (MCC) using the data of four Nordic Cancer Registries. Data for this study were drawn from the Danish, Finnish, Norwegian, and Swedish cancer registries. Standardized incidence ratios (SIRs) for MCC among NHL patients, and for NHL among MCC patients, were calculated. There were 109 838 individuals with NHL and 1411 individuals with MCC, of which 28 had joint occurrence of NHL and MCC. In 18 cases, NHL was diagnosed first, and in 10 cases, MCC was diagnosed first. The SIR for MCC after NHL was 4.34 (95% confidence interval 2.57-6.85). The SIR for NHL after MCC was 3.13 (1.50-5.77). Although the absolute frequency of joint occurrence of MCC and NHL is low, individuals suffering from one of the cancer forms have an increased risk of the other.

Skin cancer in solid organ transplant recipients: are mTOR inhibitors a game changer?

While immunosuppressive agents are necessary to prevent the rejection of transplanted organs, and are a great medical success story for protecting against early allograft loss, graft and patient survival over the long term are diminished by side effects from these same drugs. One striking long-term side effect is a high rate of skin cancer development. The skin cancers that develop in transplant recipients tend to be numerous, as well as particularly aggressive, and are therefore a major contributor to morbidity and mortality in transplant recipients. An apparent reason for the high incidence of skin cancer likely relates to suppression of immune surveillance mechanisms, but other more direct effects of certain immunosuppressive drugs are also bound to contribute to cancers of UV-exposed skin. However, over the past few years, evidence has emerged to suggest that one class of immunosuppressants, mammalian target of rapamycin (mTOR) inhibitors, could potentially inhibit skin tumour formation through a number of mechanisms that are still being studied intensively today. Therefore, in light of the high skin cancer incidence in transplant recipients, it follows that clinical trials have been conducted to determine if mTOR inhibitors can significantly reduce these post-transplant skin malignancies. Here, the problem of post-transplant skin cancer will be briefly reviewed, along with the possible mechanisms contributing to this problem, followed by an overview of the relevant clinical trial results using mTOR inhibitors.

Merkel cell carcinoma in immunosuppressed patients

Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous malignancy. The infectivity of Merkel cell polyomavirus (MCPyV), an apparent agent in MCC development, may be exacerbated with impaired immune responses. This paper reviews relevant data regarding the role of immunosuppression in the development of MCC and describes modes of immunodeficient states. Because of the inherently low incidence rate of MCC, several case studies and series are also briefly mentioned to provide a more comprehensive summary of MCC in the setting of immunosuppression. We describe immunosuppressed patients who have experienced excessive UV radiation, organ transplantation, human immunodeficiency virus infection/AIDS, autoimmune diseases, and lymphoproliferative disorders. Iatrogenic forms of immunosuppression are also highlighted. Studies that quantify risks consistently report that individuals with a history of solid organ transplantation, autoimmune diseases, AIDS, and/or lymphoproliferative diseases have a significantly elevated risk of developing MCC. Overall, immunocompromised patients also appear to have an early onset and more aggressive course of MCC, with poorer outcomes. Recommendations for multidisciplinary approaches are proposed to effectively prevent and manage MCC in these patients.

Thoracic spinal metastasis of merkel cell carcinoma in an immunocompromised patient: case report

Study Design Case report.

Objective Merkel cell carcinoma (MCC), an uncommon cutaneous neuroendocrine malignancy, is a rare cause of spinal metastasis, with only five cases previously reported. We report a rare case of MCC metastatic to the spine in an immunocompromised patient.

Methods A 55-year-old male with previously resected MCC, immunocompromised due to cardiac transplant, presented with sharp mid-thoracic back pain radiating around the trunk to the midline. Computed tomography of the thoracic spine showed a dorsal epidural mass from T6 to T8 with compression of the spinal cord. Laminectomy and subtotal tumor resection were performed, and pathology confirmed Merkel cell tumor through immunohistochemistry staining positive for cytokeratin 20 and negative for thyroid transcription factor-1.

Results Further treatment with radiation therapy was initiated, and the patient did well for 4 months after surgery, but returned with a lesion in the cervical spine. He then opted for hospice care.

Conclusions With an increasing number of immunocompromised patients presenting with back pain, MCC should be considered in the differential diagnosis of spinal metastatic disease.

Digital Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare and biologically aggressive neuroendocrine tumour of the skin. Recent analysis of a surveillance, epidemiology and end results program has shown a statistically significant increase of 8% per year in the age-adjusted rates for MCC of the skin over the past 15 years. MCC commonly presents as a painless, rapidly growing, single red or purple cutaneous nodule. Diagnosis is often delayed until histopathological examination due to the relative rarity of the disease. MCC-specific immunohistochemical markers are available for definitive diagnosis, including anticytokeratin-20-positive stain and thyroid transcription factor-1-negative stains. Because there are no phase III trials to guide management, treatment is often tailored to the individual patient by integrating surgery, radiation and chemotherapy.

Cancer risk after ABO-incompatible living-donor kidney transplantation

BACKGROUND

Recipients of ABO-incompatible (ABOi) living-donor kidney transplants often undergo more intense immunosuppression than their ABO-compatible counterparts. It is unknown if this difference leads to higher cancer risk after transplantation. Single-center studies are too small and lack adequate duration of follow-up to answer this question.

METHODS

We identified 318 ABOi recipients in the Transplant Cancer Match Study, a national linkage between the Scientific Registry of Transplant Recipients and population-based U.S. cancer registries. Seven cancers (non-Hodgkin lymphoma, Merkel cell carcinoma, gastric adenocarcinoma, hepatocellular carcinoma, thyroid cancer, pancreatic cancer, and testicular cancer) were identified among ABOi recipients. We then matched ABOi recipients to ABO-compatible controls by age, gender, race, human leukocyte antigen mismatch, retransplantation, and transplant year.

RESULTS

There was no demonstrable association between ABOi and cancer in unadjusted (incidence rate ratio, 0.83; 95% confidence interval, 0.33-1.71; P=0.3) or matched control (incidence rate ratio, 0.99; 95% confidence interval, 0.38-2.23; P=0.5) analyses.

CONCLUSION

To the extent that could be determined in this registry study, current desensitization protocols are not associated with increased risk of cancer after transplantation.

Skin cancer in organ transplant recipients

Organ transplant recipients (OTR) are at a significantly increased risk for developing a wide variety of skin cancers, particularly epithelial skin cancer, Merkel cell carcinoma and Kaposi's sarcoma. Melanoma, skin adnexal neoplasm and cutaneous lymphomas are also more common in OTR and may differ in their clinicopathologic presentation from tumors in immunocompetent patients. The accuracy of clinical diagnosis of suspected premalignant and malignant skin lesions in OTR is modest. Therefore, histopathological diagnosis is an essential element for the diagnostic workup of skin cancers and, in addition, provides important information on prognosis. Squamous cell carcinoma and intraepithelial neoplasias (actinic keratosis, squamous cell carcinoma in situ or Bowen's disease) are the most common forms of skin cancer in OTR. The risk of Merkel cell carcinoma and Kaposi's sarcoma is dramatically increased in OTR. Merkel cell carcinoma shows a highly aggressive course. Kaposi's sarcoma tends to spread to extracutaneous sites. Primary cutaneous lymphomas developing after organ transplantation are rare. The spectrum of cutaneous B cell lymphomas in OTR, in particular, differs significantly from that of the general population, with a predominance of Epstein-Barr virus-driven posttransplant lymphoproliferative disorder. This review discusses the clinical and histopathological aspects of skin cancers in OTR, the impact of dermatopathological analysis on prognosis and the understanding of the pathogenesis of these neoplasms.

Merkel cell carcinoma: diagnosis, management, and outcomes

Merkel cell carcinoma is a rare, aggressive cutaneous malignancy with high rates of recurrence, metastases, and mortality. Its nonspecific clinical presentation often delays the diagnosis, and its treatment is still controversial because of the infrequent nature of the tumor. The authors provide an overview of the current literature on epidemiology, cause, pathogenesis, staging, management, and outcomes of this disease. Effective diagnostic and treatment modalities such as wide local excision of the primary tumor, importance of sentinel node biopsy for staging, evidence for the use of adjuvant radiation therapy, and emphasis on a multidisciplinary treatment approach of Merkel cell carcinoma as it pertains to surgical practice are reviewed.

Merkel cell polyomavirus large T antigen is detected in rare cases of nonmelanoma skin cancer

BACKGROUND

Studies of Merkel cell polyomavirus (MCPyV) in nonmelanoma skin cancers (NMSC) other than Merkel cell carcinoma (MCC) produced controversial results. Therefore, we studied the prevalence of MCPyV in basal cell carcinoma (BCC) and in squamous cell carcinoma (SCC).

METHODS

Tissue specimens were analyzed for the presence of MCPyV DNA by conventional polymerase chain reaction (PCR). Expression of MCPyV large T protein was determined by immunohistochemistry.

RESULTS

MCPyV DNA was frequently detected in skin cancers by PCR, in 36 of 88 BCCs, in 21 of 75 SCCs and in 10 of 47 normal skin samples. In BCC, a significant difference in the detection rate compared to normal skin was observed. In contrast, weak reactivity for MCPyV large T antigen was detected only sporadically in immunosuppressed patients (2 of 88 BCCs, 1 of 75 SCCs). Mutations of the large T antigen of MCPyV were more frequently observed in MCC than in BCC/SCC.

CONCLUSIONS

Our results suggest that the frequent detection of the MCPyV genome in NMSC by PCR reflects ubiquitous spread of the virus. However, the low immunohistochemical detection rate of MCPyV and the lack of MCC-specific MCPyV mutations argue against an essential role of MCPyV in the development of skin cancers other than MCC.

The role of the immune response in merkel cell carcinoma

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine skin cancer. The Merkel cell polyomavirus (MCPyV) is implicated in its pathogenesis. Immune mechanisms are also implicated. Patients who are immunosuppressed have an increased risk. There is evidence that high intratumoral T-cell counts and immune transcripts are associated with favorable survival. Spontaneous regressions implicate immune effector mechanisms. Immunogenicity is also supported by observation of autoimmune paraneoplastic syndromes. Case reports suggest that immune modulation, including reduction of immune suppression, can result in tumor regression. The relationships between MCPyV infection, the immune response, and clinical outcome, however, remain poorly understood. Circulating antibodies against MCPyV antigens are present in most individuals. MCPyV-reactive T cells have been detected in both MCC patients and control subjects. High intratumoral T-cell counts are also associated with favorable survival in MCPyV-negative MCC. That the immune system plays a central role in preventing and controlling MCC is supported by several observations. MCCs often develop, however, despite the presence of humoral and cellular immune responses. A better understanding on how MCPyV and MCC evade the immune response will be necessary to develop effective immunotherapies.

Sentinel lymph node biopsy in nonmelanoma skin cancer patients

The management of lymph nodes in nonmelanoma skin cancer patients is currently still debated. Merkel cell carcinoma (MCC), squamous cell carcinoma (SCC), pigmented epithelioid melanocytoma (PEM), and other rare skin neoplasms have a well-known risk to spread to regional lymph nodes. The use of sentinel lymph node biopsy (SLNB) could be a promising procedure to assess this risk in clinically N0 patients. Metastatic SNs have been observed in 4.5-28% SCC (according to risk factors), in 9-42% MCC, and in 14-57% PEM. We observed overall 30.8% positive SNs in 13 consecutive patients operated for high-risk nonmelanoma skin cancer between 2002 and 2011 in our institution. These high rates support recommendation to implement SLNB for nonmelanoma skin cancer especially for SCC patients. Completion lymph node dissection following positive SNs is also a matter of discussion especially in PEM. It must be remembered that a definitive survival benefit of SLNB in melanoma patients has not been proven yet. However, because of its low morbidity when compared to empiric elective lymph node dissection or radiation therapy of lymphatic basins, SLNB has allowed sparing a lot of morbidity and could therefore be used in nonmelanoma skin cancer patients, even though a significant impact on survival has not been demonstrated.

Merkel cell polyomavirus: a newly discovered human virus with oncogenic potential

A marked escalation in the rate of discovery of new types of human polyomavirus has occurred over the last five years largely owing to recent technological advances in their detection. Among the newly discovered viruses, Merkel Cell Polyomavirus (MCPyV or MCV) has gained the most attention due to its link with a rare human cancer. Infection with MCPyV is common in the human population, and the virus is detected in several anatomical locations, but most frequently in skin. Study of MCPyV molecular virology has been complicated by the lack of straightforward cell culture models, but recent in vitro studies are making strides towards understanding the virus life cycle, its cellular tropism, and mode of transmission. While MCPyV shares several traditional traits with other human polyomaviruses, the burst of research since its discovery reveals insight into a virus with many unique genetic and mechanistic features. The evidence for a causal link between MCPyV and the rare neuroendocrine cancer, Merkel Cell Carcinoma (MCC), is compelling. A majority of MCCs contain clonally integrated viral DNA, express viral T antigen transcripts and protein, and exhibit an addiction to the viral large T and small t antigen oncoproteins. The MCPyV large T antigen contains MCC tumor-specific mutations that ablate its replication capacity but preserve its oncogenic functions, and the small t antigen promotes an environment favorable for cap-dependent translation. The mechanisms of MCPyV-induced transformation have not been fully elucidated, but the likely etiological role of this new polyomavirus in human cancer provides a strong opportunity to expand knowledge of virus-host interactions and viral oncology.

Merkel cell carcinoma of the head and neck: a single institutional experience

Merkel cell carcinoma (MCC) is a rare cutaneous malignancy occurring mostly in older immunocompromized Caucasian males. A growing incidence of MCC has been reported in epidemiological studies. Treatment of MCC usually consists of surgical excision, pathological lymph node evaluation, and adjuvant radiotherapy. This paper reports the experience of a single tertiary center institution with 17 head and neck Merkel cell carcinoma patients. Median followup for the cohort was 37.5 months. After five years, recurrence-free survival, disease specific survival, and overall survival were 85%, 90%, and 83%, respectively. Our limited data support the use of adjuvant radiotherapy. We also report two cases of MCC located at the vestibule of the nose and two cases of spontaneous regression after diagnostic biopsy. About 40% of our patients were referred to our center for surgical revision and pathological lymph node evaluation. Increased awareness of MCC and an interdisciplinary approach are essential in the management of MCC.

Incidence, risk factors, and preventative management of skin cancers in organ transplant recipients: a review of single- and multicenter retrospective studies from 2006 to 2010

BACKGROUND

Organ transplant recipients (OTRs) taking immunosuppressants are at high risk of skin cancer, which is the most common malignant condition in OTRs, so dermatologic surveillance is important for OTRs.

OBJECTIVES

To characterize the most common skin cancers arising from chronic immunosuppression in OTRs.

METHODS

A PubMed search for retrospective single- and multicenter studies reporting skin cancer incidence from 2006 to 2010 was undertaken. Data regarding each study's immunosuppressive regimen, affected skin cancer cohort, and associated risk factors were extracted.

RESULTS

Thirty-six articles that met our inclusion criteria reported incidences of nonmelanoma skin cancer (NMSC), Kaposi's sarcoma, melanoma, and Merkel cell carcinoma. NMSC was the most commonly reported cancer of all skin cancers after transplantation. Common risk factors were sex, age, sunlight exposure, and immunosuppressive agent-related (duration, type).

CONCLUSION

Sun education programs and frequent screenings in organ transplant clinics have provided the best preventative strategies after transplantation, although the characteristics of the immunosuppressive regimen also play an important role. Thus, the adjuvant strategy of modifying immunosuppression may be effective when confronting severe transplant-associated skin cancer. Although the decision-making process for curbing levels of immunosuppression is difficult, further long-term, randomized controlled studies should assess the effect of using less immunosuppressant medication while preserving graft function.

MCV and Merkel cell carcinoma: a molecular success story

Merkel cell polyomavirus (MCV), discovered in 2008, is clonally integrated in ~80% Merkel cell carcinoma (MCC). MCV is a common skin flora and initiates cancer in susceptible hosts only after it acquires a precise set of mutations that render it replication incompetent. Both MCV large and small T proteins promote cancer cell survival and proliferation. Large T targets pocket proteins regulating cell cycle transit while small T activates cap-dependent translation critical for cancer cell growth. These findings already have led to new diagnostics and clinical trials to target MCV-induced survivin and to promote antitumor immunity. In four years, the cause, diagnosis and therapy for an intractable cancer has been changed due to the molecular discovery of MCV.

Rising incidence of Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare, aggressive, skin cancer of obscure histogenesis, the incidence of which is rising. There is no consensus on the optimal treatment. Our aim was to evaluate the staging, investigation, treatment, and follow-up of MCC in eastern Denmark, and to investigate the incidence. We suggest guidelines for treatment. First we reviewed the medical records of 51 patients diagnosed with MCC from 1995 until 2006 in eastern Denmark. The nation-wide incidence of MCC was extracted from the Danish Cancer Registry for the calculations for the period 1986-2003. We reviwed published papers about MCC based on a MEDLINE search. Fourteen of the 51 patients developed recurrence, and 37 (73%) died during the study period. Mean follow-up was 13 months (range 1-122). A total of 153 patients were identified in the Danish Cancer Registry, and showed that incidence rates had increased 5.4 fold over the 18 year period from 1986 until 2003. Rates were highest in people over the age of 65. Recommended treatment with curative intent includes excision of the primary tumour with wide margins, excision of the sentinel node, computed tomogram (CT) or positron emission tomography (PET) of the thorax and abdomen, and adjuvant radiotherapy to the surgical bed. In the case of advanced disease, systemic palliative chemotherapy remains a possibility. There is a need for prospective multicentre evaluation of staging investigations and treatment of MCC.

Increased incidence of chronic lymphocytic leukaemia and lymphomas in patients with Merkel cell carcinoma - a population based study of 335 cases with neuroendocrine skin tumour

Merkel cell carcinoma (MCC) is a rare aggressive skin tumour that appears to be associated with a large number of other tumours. We collected all reported cases in Israel and estimated its association with other tumours, including haematological malignancies. The population based Israel Cancer Registry identified 335 patients with MCC diagnosed between1989 and 2010. Ninety-seven percent were in the Jewish population; median age at diagnosis for Jewish patients was 73·4 and 55·6 years for the Arab population. Other associated malignancies were encountered in 92 patients (27·4%) with MCC (90 Jews, two Arabs). Of the Jewish cases, 66 presented with an associated malignancy before, and 24 after, the diagnosis of MCC. Solid tumours were not significantly increased among patients with MCC. Thirty-one of these associated cancers (34·4%) were haemato-oncological malignancies, 24 were detected before and seven after the diagnosis of MCC. The standardized incidence ratio (SIR) for haematological malignancy was 3·67 for males and 3·62 for females, and the most frequent haemato-oncological neoplasias recorded were chronic lymphocytic leukaemia (45%) and lymphomas (29%). Although MCC is rare, clinicians should be aware of the possible association with B-cell lymphoproliferative disorders when evaluating patients with neuroendocrine skin tumours.

Merkel cell carcinoma - a population-based epidemiological study in Finland with a clinical series of 181 cases

BACKGROUND

Merkel cell carcinoma (MCC) is a rare malignancy of the skin, and its incidence is reported to be rising. The purpose of this study was to calculate its incidence and survival ratios, and to describe the clinical characteristics of Merkel cell carcinoma patients in Finland.

METHODS

We calculated the incidence of MCC based on data from the Finnish Cancer Registry. In addition, patient files from hospitals and primary health care centres were reviewed for detailed data on the treatment and disease recurrence of 181 patients diagnosed with MCC in Finland during 1983-2004, and relative survival ratios were calculated for them.

RESULTS

The incidence (per 100,000) of MCC in Finland in 1989-2008 was 0.11 for men and 0.12 for women, adjusted for age to the world standard population. The mean age at diagnosis was 76 years (range 27-100), and 69% of the patients were women. The most common site of the primary tumour was the head and neck (53%). No extra benefit was gained from a wide surgical margin (≥ 2 cm) compared to a margin of 0.1-0.19 cm, but an intralesional excision was more often associated with local recurrence. None of the patients with Stage I-II disease who had received postoperative radiotherapy to the tumour bed had a local recurrence. The 5-year relative survival ratio amongst men was 36% (95% confidence interval 20-54%), and amongst women 69% (56 to -82%).

CONCLUSIONS

MCC is a rare disease in Finland, with incidence rates similar to those in the other Nordic countries. Our results support the view that complete excision with clear margins and post operative radiotherapy decrease local recurrences.

Epidemiology and survival of Merkel cell carcinoma in the Netherlands. A population-based study of 808 cases in 1993-2007

BACKGROUND

Merkel cell carcinoma (MCC) is a rare and highly malignant neuroendocrine tumour, predominantly located on sun-exposed areas of the skin. The aim of this study was to evaluate data in the Netherlands concerning incidence, stage, age, sex, location, treatment and survival.

METHODS

Using nationwide data from the Netherlands Cancer Registry from 1993 to 2007, we compared 808 MCCs with European data and the US Surveillance, Epidemiology and End Results (SEER) Program.

RESULTS

The annual age standardised incidence rate per million of MCC increased from 1.7 in 1993-1997 to 3.5 in 2003-2007. Median age at diagnosis was 76 years. The most common location was the head and neck. Three quarters of patients had localised disease, 16% regional and 6% distant metastasis. Surgery was performed in 89% of patients, with adjuvant radiotherapy in 26% of them. One-, five- and ten-year relative survival was 85%, 62% and 47%, respectively. Negative predictive factors for the risk of death were male sex, increasing T-stage, regional and distant metastasis and no treatment. Survival after combined surgery and radiotherapy was borderline significantly better than surgery alone (HR 0.82, p=0.09). Our results are comparable to SEER data except for the ratio localised/regional disease. We observed less regional cases (16% versus 31%); while ten-year survival of localised cases was lower (51% versus 71%).

CONCLUSIONS

MCC incidence rates have doubled in the Netherlands over the period 1993-2007. The relatively high number of localised cases and their relatively low survival as compared to SEER data suggest that a substantial proportion is undertreated.

Vascular invasion is an early event in pathogenesis of Merkel cell carcinoma

This study investigated vascular and especially lymphovascular invasion in primary Merkel cell carcinoma and its value as a prognostic factor. Paraffin-embedded blocks prepared from tumor samples obtained from 126 patients diagnosed with Merkel cell carcinoma in 1979-2004 were immunohistochemically stained using antibodies CD31 and D2-40 to detect intravascular tumor emboli. This finding was compared with the clinical data and the disease outcome. Intravascular tumor cells were observed in 117 (93%) of the samples. The majority, 83 (66%), showed only lymphovascular invasion. Only blood vascular invasion was seen in four (3%) samples. In all, 30 (24%) samples demonstrated both lymphovascular invasion and blood vascular invasion. In only nine (7%) samples, there was no invasion within the vascular structures. The tumors lacking invasion were significantly smaller (P<0.01 and alpha=0.050) than those with vascular invasion, although lymphovascular invasion was observed even in the smallest tumor (0.3 cm) of this study. Already in the early stages of the disease, Merkel cell carcinoma seems to have the capacity to penetrate vessel walls. Our finding of the high frequency of lymphovascular invasion might therefore explain the extremely aggressive clinical behavior of Merkel cell carcinoma. This may support the role of sentinel node biopsy even in the case of very small primary Merkel cell carcinoma tumors.