PD-1 and TIGIT coexpression identifies a circulating CD8 T cell subset predictive of response to anti-PD-1 therapy.

BACKGROUND: Clinical benefit from programmed cell death 1 receptor (PD-1) inhibitors relies on reinvigoration of endogenous antitumor immunity. Nonetheless, robust immunological markers, based on circulating immune cell subsets associated with therapeutic efficacy are yet to be validated. METHODS: We isolated peripheral blood mononuclear cell from three independent cohorts of melanoma and Merkel cell carcinoma patients treated with PD-1 inhibitor, at baseline and longitudinally after therapy. Using multiparameter flow cytometry and cell sorting, we isolated four subsets of CD8+ T cells, based on PD-1 and TIGIT expression profiles. We performed phenotypic characterization, T cell receptor sequencing, targeted transcriptomic analysis and antitumor reactivity assays to thoroughly characterize each of these subsets. RESULTS: We documented that the frequency of circulating PD-1+TIGIT+ (DPOS) CD8+ T-cells after 1 month of anti-PD-1 therapy was associated with clinical response and overall survival. This DPOS T-cell population was enriched in highly activated T-cells, tumor-specific and emerging T-cell clonotypes and T lymphocytes overexpressing CXCR5, a key marker of the CD8 cytotoxic follicular T cell population. Additionally, transcriptomic profiling defined a specific gene signature for this population as well as the overexpression of specific pathways associated with the therapeutic response. CONCLUSIONS: Our results provide a convincing rationale for monitoring this PD-1+TIGIT+ circulating population as an early cellular-based marker of therapeutic response to anti-PD-1 therapy.

Circulating Tumor Cell Detection and Polyomavirus Status in Merkel Cell Carcinoma.

The incidence of Merkel cell carcinoma (MCC), a rare and highly metastatic skin malignancy, has sharply increased in the last decade. Clinical biomarkers are urgently needed for MCC prognosis, treatment response monitoring, and early diagnosis of relapse. The clinical interest of circulating tumors cells (CTCs) has been validated in many solid cancers. The aim of this study was to compare CTC detection and characterization in blood samples of patients with MCC using the CellSearch System and the RosetteSep -DEPArray workflow, an innovative procedure to enrich, detect and isolate single CTCs. In preliminary experiments (using spiked MCC cell lines) both methods allowed detecting very few MCC cells. In blood samples from 19 patients with MCC at different stages, CellSearch detected MCC CTCs in 26% of patients, and the R-D workflow in 42% of patients. The detection of CTC-positive patients increased to 52% by the cumulative positivity rate of both methodologies. Moreover, Merkel cell polyomavirus DNA, involved in MCC oncogenesis, was detected in tumor biopsies, but not in all single CTCs from the same patient, reflecting the tumor heterogeneity. Our data demonstrate the possibility to detect, isolate and characterize CTCs in patients with MCC using two complementary approaches.

Circulating Cell-Free miR-375 as Surrogate Marker of Tumor Burden in Merkel Cell Carcinoma.

PURPOSE: Merkel cell carcinoma (MCC) is an aggressive skin cancer with neuroendocrine differentiation. There is an unmet need for MCC-specific blood-based surrogate biomarkers of tumor burden; circulating cell-free miRNA may serve this purpose. EXPERIMENTAL DESIGN: Expression of miR-375 was quantified in 24 MCC and 23 non-MCC cell lines, 67 MCC and 58 non-MCC tumor tissues, sera of 2 preclinical MCC models, and sera of 109 patients with MCC and 30 healthy controls by nCounter human-v2-miRNA expression or miR-375-specific real-time PCR assays. The patients' sera consisted of two retrospective (discovery and training) and two prospective (validation) cohorts. RESULTS: miR-375 expression was high in MCC cell lines and tissues compared with non-MCCs. It was readily detected in MCC-conditioned medium and sera of preclinical models bearing MCC xenografts. miR-375 levels were higher in sera from tumor-bearing patients with MCC than in tumor-free patients or healthy controls (P < 0.0005). Moreover, miR-375 serum levels correlated with tumor stage in tumor-bearing (P = 0.037) but not in tumor-free (P = 0.372) patients with MCC. miR-375 serum level showed high diagnostic accuracy to discriminate tumor-bearing and tumor-free patients with MCC as demonstrated by ROC curve analysis in the retrospective cohorts (AUC = 0.954 and 0.800) as well as in the prospective cohorts (AUC = 0.929 and 0.959). miR-375 serum level reflected dynamic changes in tumor burden of patients with MCC during therapeutic interventions. CONCLUSIONS: Circulating cell-free miR-375 proved as a surrogate marker for tumor burden in MCC without restriction to polyomavirus positivity; it thus appears to be useful for therapy monitoring and the follow-up of patients with MCC.

Cytokine release syndrome after radiation therapy: case report and review of the literature.

BACKGROUND: Cytokine release syndrome (CRS) has been reported after immunologic manipulations, most often through therapeutic monoclonal antibodies. To our knowledge, CRS after radiation therapy (RT) for cancer has not been reported before. The development of unusual clinical signs and symptoms after RT led us to investigate the possibility of CRS after RT and review the medical literature on this topic. CASE PRESENTATION: A 65 year-old man with untreated chronic lymphocytic leukemia and recurrent, metastatic Merkel cell carcinoma undergoing anti-programmed death 1 (PD1) immunotherapy was referred for palliative RT to sites of progressing metastases. Within hours of each weekly dose of RT, he experienced fever, tachycardia, hypotension, rash, dyspnea, and rigors. Based on clinical suspicion for CRS, blood cytokine measurements were performed 1 h after the second and third dose of RT and demonstrated tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) levels approximately ten-fold higher than normal. These were near normal immediately prior to the third dose of RT, and resolved to normal levels 3 weeks after RT. He experienced rapid regression of irradiated tumors, with development of new sites of metastases soon thereafter. A literature review revealed no clinical cases of CRS after RT for cancer. CONCLUSIONS: RT during anti-PD1 immunotherapy in a patient with underlying immune dysfunction appeared to be the putative mediator of an immune process which yielded significant increases in pro-inflammatory cytokines, and produced the clinical symptoms meeting the definition of grade 3 CRS. This case demonstrates the capability of RT to elicit immune-related adverse events.

Merkel Cell Carcinomas Arising in Autoimmune Disease Affected Patients Treated with Biologic Drugs, Including Anti-TNF.

Purpose: The purpose of this investigation was to characterize Merkel cell carcinomas (MCC) arisen in patients affected by autoimmune diseases and treated with biologic drugs.Experimental Design: Serum samples from patients with MCC were analyzed for the presence and titer of antibodies against antigens of the oncogenic Merkel cell polyomavirus (MCPyV). IgG antibodies against the viral oncoproteins large T (LT) and small T (ST) antigens and the viral capsid protein-1 were analyzed by indirect ELISA. Viral antigens were recombinant LT/ST and virus-like particles (VLP), respectively. MCPyV DNA sequences were studied using PCR methods in MCC tissues and in peripheral blood mononuclear cells (PBMC). Immunohistochemical (IHC) analyses were carried out in MCC tissues to reveal MCPyV LT oncoprotein.Results: MCPyV DNA sequences identified in MCC tissues showed 100% homology with the European MKL-1 strain. PBMCs from patients tested MCPyV-negative. Viral DNA loads in the three MCC tissues were in the 0.1 to 30 copy/cell range. IgG antibodies against LT/ST were detected in patients 1 and 3, whereas patient 2 did not react to the MCPyV LT/ST antigen. Sera from the three patients with MCC contained IgG antibodies against MCPyV VP1. MCC tissues tested MCPyV LT-antigen-positive in IHC assays, with strong LT expression with diffuse nuclear localization. Normal tissues tested MCPyV LT-negative when employed as control.Conclusions: We investigated three new MCCs in patients affected by rheumatologic diseases treated with biologic drugs, including TNF. A possible cause-effect relationship between pharmacologic immunosuppressive treatment and MCC onset is suggested. Indeed, MCC is associated with MCPyV LT oncoprotein activity. Clin Cancer Res; 23(14); 3929-34. ©2017 AACR.

Merkel cell polyomavirus IgG antibody levels are associated with progression to AIDS among HIV-infected individuals.

The association of Merkel cell polyomavirus (MCPyV) with Merkel cell carcinoma (MCC) in immunocompromised individuals has been revealed in a number of surveys. The study of MCPyV specific antibody titers and viral loads in such patients has a great attraction for research groups interested in viral reactivation. In this cross-sectional study to evaluate MCPyV antibody titer, DNA prevalence and viral load in peripheral blood mononuclear cells (PBMCs), we examined 205 HIV-1 infected patients and 100 un-infected controls. The HIV-1 infected patients divided into two groups (HIV/AIDS and non-AIDS) according to their CD4 status. Total IgG antibody titer against MCPyV was analyzed by virus like particle (VLP)-based enzyme linked immunosorbent assay (ELISA). Presence of MCPyV-DNA in subject's PBMCs was examined by quantitative real-time PCR assay. Levels of anti-MCPyV IgG in HIV/AIDS patients were significantly higher than those in non-AIDS HIV-infected and control subjects (p value = <0.001). The prevalence rate of MCPyV-DNA in PBMCs of HIV/AIDS, non-AIDS HIV-infected and un-infected controls were 17%, 16%, and 14% respectively. The MCPyV viral load among the groups ranged between 0.15 to 2.9 copies/103cells (median, 1.9 copies/103cells), with no significant difference between the studied populations (p value = 0.3).

Paraneoplastic cerebellar degeneration and lambert-eaton myasthenia in a patient with merkel cell carcinoma and voltage-gated calcium channel antibodies.

INTRODUCTION: Merkel cell carcinoma is a rare cutaneous, aggressive tumor. Although it shares many neuroendocrine features with small cell lung carcinoma, it has only occasionally been reported with paraneoplastic neurological syndromes. METHODS: A healthy 67-year-old man developed acute ataxia, vertigo, and nausea. Subsequently he also developed dysarthria, diplopia, xerostomia, fatigability and progressive anorexia. He underwent a full diagnostic workup and was found to have a high titer of voltage-gated calcium channel antibodies in serum and cerebrospinal fluid, neurophysiological findings compatible with Lambert-Eaton myasthenia and neurological signs compatible with cerebellar degeneration. RESULTS: A positron emission tomography study revealed a hypermetabolic lesion in the axilla, subsequently biopsied and consistent with Merkel cell carcinoma. CONCLUSIONS: In most previous reports, neurological symptoms preceded the Merkel cell carcinoma diagnosis, and the primary localization was in lymph nodes. This tumor should be considered in patients with paraneoplastic syndrome, and particularly Lambert-Eaton myasthenia after exclusion of small cell lung carcinoma. Muscle Nerve 56: 998-1000, 2017.

A high neutrophil-to-lymphocyte ratio as a potential marker of mortality in patients with Merkel cell carcinoma: A retrospective study.

BACKGROUND: The prognostic relevance of a high blood neutrophil-to-lymphocyte ratio (NLR) has been reported in many cancers, although, to our knowledge, not investigated in patients with Merkel cell carcinoma (MCC) to date. OBJECTIVE: We assessed whether the NLR at baseline was associated with specific survival and recurrence-free survival in MCC. METHODS: We retrospectively included MCC cases between 1999 and 2015 and collected clinical data, blood cell count at baseline, and outcome. A Cox model was used to identify factors associated with recurrence and death from MCC. RESULTS: Among the 75 patients included in the study, a high NLR at baseline (NLR ≥4) was associated with death from MCC in univariate (hazard ratio 2.76, 95% confidence interval 1.15-6.62, P = .023) and multivariate (hazard ratio 3.30, 95% confidence interval 1.21-9.01, P = .020) analysis, but not with recurrence. LIMITATIONS: Because of the retrospective design, we excluded patients with missing data and not all confounding factors that may influence the NLR were available. CONCLUSION: A high NLR at baseline was independently associated with specific mortality in patients with MCC. The NLR seems to constitute an easily available and inexpensive prognostic biomarker at baseline.

Evaluating blood levels of neuron specific enolase, chromogranin A, and circulating tumor cells as Merkel cell carcinoma biomarkers.

BACKGROUND: Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine skin cancer. Although used to monitor MCC patients, the clinical utility of neuron-specific enolase (NSE) and chromogranin A (ChrA) blood levels is untested. EpCAM-positive circulating tumor cells (CTC) reflect disease status in several epithelial tumors. Here we investigate the use of NSE and ChrA blood levels and CTC counts as biomarkers for MCC disease behavior. METHODS: NSE and ChrA blood levels from 60 patients with MCC were retrospectively analyzed; 30 patients were additionally screened for CTC. Biomarker values were correlated to clinical parameters. RESULTS: Despite routine use by some physicians, NSE and ChrA blood levels did not correlate with progression free survival, disease specific survival, or MCC recurrence. We found CTC in 97% of tested MCC patients. CTC counts were elevated in patients with active disease, suggesting their potential use in monitoring MCC. CONCLUSIONS: NSE and ChrA levels were not effective in predicting outcomes or detecting recurrences of MCC. In contrast, CTC counts have potential utility as a biomarker for MCC disease behavior.

Absolute lymphocyte count: a potential prognostic factor for Merkel cell carcinoma.

BACKGROUND: Absolute lymphocyte count (ALC) is a laboratory value commonly obtained during workup of patients with Merkel cell carcinoma (MCC). OBJECTIVE: We report the prognostic impact of ALC as a surrogate of immune status in MCC. METHODS: A complete blood cell count was available for 64 patients with MCC in the month before definitive surgery, chemotherapy, or radiation. Statistical analysis was performed with classification and regression tree analysis, log rank test, and Cox model. RESULTS: Median overall survival (OS) for the cohort was 97 months. Median OS for patients with an ALC less than 1.1 k/mm(3) was 18.8 versus 110.1 months for those with ALC greater than or equal to 1.1 k/mm(3) (P = .002, hazard ratio 0.29). Multivariate analysis of OS controlling for ALC, sex, stage, adjuvant chemotherapy, hematologic malignancy, and immunosuppression demonstrated ALC as a prognostic factor (P = .03). Disease-free survival at 36 months for ALC less than 1.1 k/mm(3) was 26.9% versus 64.4% for those with ALC greater than or equal to 1.1 k/mm(3) (P = .01). ALC was not a significant predictor for disease-free survival on multivariate analysis (P = .12). LIMITATIONS: This is a single-institution retrospective data set. CONCLUSION: ALC is associated with OS but not disease-free survival in MCC using a threshold of less than 1.1 k/mm(3). This test may provide additional prognostic information for patients with MCC.

Clinical utility of a circulating tumor cell assay in Merkel cell carcinoma.

BACKGROUND: Quantitation of circulating tumor cells (CTCs) has utility in managing breast, colon, and prostate carcinomas. OBJECTIVE: We sought to determine whether a commercially available CTC assay provides prognostic information in Merkel cell carcinoma (MCC), insight into treatment responses, or both. METHODS: We analyzed CTCs in 52 specimens from 34 patients with MCC. RESULTS: The presence of CTCs correlated with extent of disease at blood draw (P = .004). Among 15 patients with regional nodal disease, CTC-negative patients had 80% disease-specific survival at 2 years after the test, versus 29% for CTC-positive patients (P = .015). Among the entire cohort, those without CTCs had 72% MCC-specific survival whereas CTC-positive patients had 25% survival (n = 34, median follow-up 19 months, P = .0003). Fifty seven percent of patients with MCC had a cytokeratin "dot" visible in 20% or more of CTCs, a feature that was absent among CTCs from other carcinomas (0 of 13 cases). LIMITATIONS: CTC assay was performed at variable times after diagnosis and heterogeneity in extent of disease affects interpretability of the data. CONCLUSION: CTC detection in MCC is feasible and appears to add prognostic information, particularly in patients with regional nodal disease. It may also assist clinical management in certain situations, including differentiating metastatic MCC cells from those of other carcinomas.

Prospective study of Merkel cell polyomavirus and risk of Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is a rare type of skin cancer that has a characteristically increased incidence among immunosuppressed subjects. The DNA of Merkel cell polyomavirus (MCV) is regularly found in most MCC tumors. We investigated whether Merkel cell polyomavirus (MCV) infection increases the risk for future MCC. Two large biobank cohorts (Southern Sweden Microbiology Biobank and the Janus Biobank), containing samples from 856,000 healthy donors, were linked to the Cancer Registries in Sweden and Norway to identify cases of MCC occurring up to 30 years after donation of a serum sample. For each of the 22 cases (nine males and 13 females), four matched controls were included. The serum samples were analyzed with an MCV neutralization assay and for IgG antibodies to MCV pseudovirions, using JC polyomavirus and cutaneous human papillomaviruses as control antigens. An increased risk for future MCC was associated both with high levels of MCV antibodies [OR 4.4, 95% CI 1.3-17.4] and with MCV neutralizing activity (OR 5.3, 95% CI 1.3-32.3). In males, MCV seropositivity was not associated to MCC risk, whereas the risk was strongly increased in females, both for high levels of MCV antibodies (OR 7.0, 95% CI 1.6-42.8) and for MCV neutralizing activity (OR 14.3, 95% CI 1.7-677). In conclusion, we found prospective evidence that MCV infection is associated with an increased risk for future MCC, in particular among females.

Tumor lysis syndrome in a patient with merkel cell carcinoma and provoked pathologic sequence of acute kidney injury, reduced clearance of carboplatin and fatal pancytopenia.

BACKGROUND: Merkel cell carcinoma (MCC) is a rare, highly malignant cancer of the skin primarily affecting the elderly, with a tendency for local recurrence and regional lymph node metastasis. It is very unusual for this kind of tumor to induce clinically apparent tumor lysis syndrome (TLS) which is a consequence of spontaneous cytolysis or massive tumor cell lysis, beginning a few hours after the initiation of treatment. CASE REPORT: We report here on a patient with metastatic MCC, who developed TLS following combination chemotherapy with carboplatin and etoposide. CONCLUSION: The evolving acute kidney injury (AKI) provoked a pathologic sequence of reduced renal clearance leading to protracted clearance of carboplatin and subsequent fatal pancytopenia. When AKI occurs in close association with the administration of carboplatin, the institution of rescue hemodialysis is recommended to decrease plasma carboplatin levels and avoid this lethal complication.

Merkel cell polyomavirus-specific CD8⁺ and CD4⁺ T-cell responses identified in Merkel cell carcinomas and blood.

PURPOSE: Merkel cell polyomavirus (MCPyV) is prevalent in the general population, integrates into most Merkel cell carcinomas (MCC), and encodes oncoproteins required for MCC tumor growth. We sought to characterize T-cell responses directed against viral proteins that drive this cancer as a step toward immunotherapy. EXPERIMENTAL DESIGN: Intracellular cytokine cytometry, IFN-γ enzyme-linked immunospot (ELISPOT) assay, and a novel HLA-A*2402-restricted MCPyV tetramer were used to identify and characterize T-cell responses against MCPyV oncoproteins in tumors and blood of MCC patients and control subjects. RESULTS: We isolated virus-reactive CD8 or CD4 T cells from MCPyV-positive MCC tumors (2 of 6) but not from virus-negative tumors (0 of 4). MCPyV-specific T-cell responses were also detected in the blood of MCC patients (14 of 27) and control subjects (5 of 13). These T cells recognized a broad range of peptides derived from capsid proteins (2 epitopes) and oncoproteins (24 epitopes). HLA-A*2402-restricted MCPyV oncoprotein processing and presentation by mammalian cells led to CD8-mediated cytotoxicity. Virus-specific CD8 T cells were markedly enriched among tumor infiltrating lymphocytes as compared with blood, implying intact T-cell trafficking into the tumor. Although tetramer-positive CD8 T cells were detected in the blood of 2 of 5 HLA-matched MCC patients, these cells failed to produce IFN-γ when challenged ex vivo with peptide. CONCLUSIONS: Our findings suggest that MCC tumors often develop despite the presence of T cells specific for MCPyV T-Ag oncoproteins. The identified epitopes may be candidates for peptide-specific vaccines and tumor- or virus-specific adoptive immunotherapies to overcome immune evasion mechanisms in MCC patients.

Antibodies to merkel cell polyomavirus T antigen oncoproteins reflect tumor burden in merkel cell carcinoma patients.

Merkel cell polyomavirus (MCPyV) is a common infectious agent that is likely involved in the etiology of most Merkel cell carcinomas (MCC). Serum antibodies recognizing the MCPyV capsid protein VP1 are detectable at high titer in nearly all MCC patients and remain stable over time. Although antibodies to the viral capsid indicate prior MCPyV infection, they provide limited clinical insight into MCC because they are also detected in more than half of the general population. We investigated whether antibodies recognizing MCPyV large and small tumor-associated antigens (T-Ag) would be more specifically associated with MCC. Among 530 population control subjects, these antibodies were present in only 0.9% and were of low titer. In contrast, among 205 MCC cases, 40.5% had serum IgG antibodies that recognize a portion of T-Ag shared between small and large T-Ags. Among cases, titers of T-Ag antibodies fell rapidly (∼8-fold per year) in patients whose cancer did not recur, whereas they rose rapidly in those with progressive disease. Importantly, in several patients who developed metastases, the rise in T-Ag titer preceded clinical detection of disease spread. These results suggest that antibodies recognizing T-Ag are relatively specifically associated with MCC, do not effectively protect against disease progression, and may serve as a clinically useful indicator of disease status.

Antibodies to cerebellar nerve fibres in two patients with paraneoplastic cerebellar ataxia.

The aim of this study was to characterize two new atypical anti-neuronal antibodies using an immunohistochemical method on rat cerebellum and Western blot techniques with primate cerebellar tissue and with recombinant neuronal proteins. Atypical sera from two patients with paraneoplastic neurological syndromes associated with different tumours were detected. Case number 1 presented cerebellar degeneration and Merkel cell carcinoma and case number 2 paraneoplastic brainstem encephalitis and malignant fibrous histiocytoma. By immunohistochemistry, the two new atypical antibodies showed a similar fibrillar positivity in the molecular and granular layers and around the Purkinje cells. The dot blot with recombinant neuronal proteins (HuD, NOVA-1, CDR62/Yo, Amphiphysin) was negative, whereas the Western blot with neuronal antigens of primate cerebellum identified two different proteins with molecular weights (64 kD in case number 1, and 70 kD in case number 2). In conclusion, the two new antibody reactivities against nerve fibres should be integrated into the diagnostic paraneoplastic neurological syndromes guidelines.

Anti-Hu antibodies in Merkel cell carcinoma.

Anti-Hu antibody is an antineuronal autoantibody found in a subset of patients with paraneoplastic neurological disease. The antibody was first associated with small cell carcinoma of the lung and is most often used as a marker for this neoplasm in patients presenting with suspected paraneoplastic syndromes. Here we report a patient with a multifaceted neurological disorder in the setting of Merkel cell carcinoma. The patient's serum contained antibodies against the Hu antigen, and the expression of the Hu antigen was demonstrated in the patient's tumor.

Multiple hamartoma syndrome (Cowden's disease) associated with renal cell carcinoma and primary neuroendocrine carcinoma of the skin (Merkel cell carcinoma).

A case of multiple hamartoma syndrome (Cowden's disease) associated with renal cell adenocarcinoma and primary neuroendocrine carcinoma of the skin is described. Neither of these neoplasms has been documented previously in association with this genodermatosis. A search for epidermal growth factor receptor (c-erb-B protooncogene) gene abnormalities in the kidney, liver, and thyroid, as well as in tissue of the primary neuroendocrine carcinoma, was negative. Serum obtained from the patient before his death contained elevated levels of both chromogranin A (2641 ng/mL; normal level, less than 20 ng/mL) and calcitonin (517 pg/mL; normal level, less than 200 pg/mL), suggesting that the patient's principal tumor was neuroendocrine in origin.