Serge Guyétant

High Levels of Antibodies Against Merkel Cell Polyomavirus Identify a Subset of Patients With Merkel Cell Carcinoma With Better Clinical Outcome

PURPOSE A new human polyomavirus, Merkel cell polyomavirus (MCV), was identified in 2008 in tumor tissue of patients with Merkel cell carcinoma (MCC), a relatively rare human skin cancer. In this study, we investigated patients with MCC and controls for the presence of antibodies against MCV and their association with clinical characteristics. PATIENTS AND METHODS Antibodies against MCV were investigated by enzyme-linked immunosorbent assay in 68 patients with MCC and 82 controls using VP1 virus-like particles produced in insect cells. RESULTS Antibodies against MCV were detected in all patients with MCC and in 85% of controls. However, high antibody titers (> 10,000) were rarely observed in controls (7.3%) and they were detected in 64.7% of patients with MCC (P < .001) in contrast to the absence of VP1 expression in tumor samples. In addition, the geometric mean titer of anti-MCV in patients with MCC was around 14 times higher than that observed in MCV-positive controls (P < .001) and was not correlated with tumor viral load. High antibody titers were not found to be associated with any subject or tumor characteristics, but better progression-free survival was observed in patients with high antibody titers (hazard ratio, 4.6; 95% CI, 1.7 to 12.2; P = .002). CONCLUSION High titers of MCV antibodies in a much higher proportion of patients with MCC than in controls confirmed the association between MCV infection and MCC. The findings also indicated that a better progression-free survival occurred in patients with high MCV antibody titers and suggested that there are at least two distinct etiologic causes of MCC.

Generation of Merkel Cell Polyomavirus (MCV)-Like Particles and Their Application to Detection of MCV Antibodies

ABSTRACT The genome of a new human polyomavirus, known as Merkel cell polyomavirus (MCV), has recently been reported to be integrated within the cellular DNA of Merkel cell carcinoma (MCC), a rare human skin cancer. To investigate MCV seroprevalence in the general population, we expressed three different MCV VP1 in insect cells using recombinant baculoviruses. Viruslike particles (VLPs) were obtained with only one of the three VP1 genes. High-titer antibodies against VP1 VLPs were detected in mice immunized with MCV VLPs, and limited cross-reactivity was observed with BK polyomavirus (BKV) and lymphotropic polyomavirus (LPV). MCV antibodies were detected in 77% of the general population, with no variations according to age.

Merkel cell polyomavirus strains in patients with merkel cell carcinoma.

We investigated whether Merkel cell carcinoma (MCC) patients in France carry Merkel cell polyomavirus (MCPyV) and then identified strain variations. All frozen MCC specimens and 45% of formalin-fixed and paraffin-embedded specimens, but none of the non-MCC neuroendocrine carcinomas specimens, had MCPyV. Strains from France and the United States were similar.

Prognostic value of antibodies to Merkel cell polyomavirus T antigens and VP1 protein in patients with Merkel cell carcinoma.

Merkel cell polyomavirus (MCPyV) is the main aetiological agent of Merkel cell carcinoma (MCC). Serum antibodies against the major MCPyV capsid protein (VP1) are detected in the general population, whereas antibodies against MCPyV oncoproteins (T antigens) have been reported specifically in patients with MCC.

Vitamin D deficiency is associated with greater tumor size and poorer outcome in Merkel cell carcinoma patients.

Merkel cell polyomavirus has been recognized to be associated with Merkel cell carcinoma (MCC), but the evolution of this cancer probably depends on various factors. Vitamin D deficiency, defined by serum 25‐hydroxyvitamin D levels <50 nmol/L, seems to influence cancer behavior and progression, but has never been assessed in MCC patients.

Beneficial role of overexpression of TFPI-2 on tumour progression in human small cell lung cancer

Tissue factor pathway inhibitor‐2 (TFPI‐2) is a potent inhibitor of plasmin, a protease which is involved in tumour progression by activating (MMPs). This therefore makes TFPI‐2 a potential inhibitor of invasiveness and the development of metastases. In this study, low levels of TFPI‐2 expression were found in 65% of patients with small cell lung cancer (SCLC), the most aggressive type of lung cancer. To study the impact of TFPI‐2 in tumour progression, TFPI‐2 was overexpressed in NCI‐H209 SCLC cells which were orthotopically implanted in nude mice. Investigations showed that TFPI‐2 inhibited lung tumour growth. Such inhibition could be explained in vitro by a decrease in tumour cell viability, blockade of G1/S phase cell cycle transition and an increase in apoptosis shown in NCI‐H209 cells expressing TFPI‐2. We also demonstrated that TFPI‐2 upregulation in NCI‐H209 cells decreased MMP expression, particularly by downregulating MMP‐1 and MMP‐3. Moreover, TFPI‐2 inhibited phosphorylation of the MAPK signalling pathway proteins involved in the induction of MMP transcripts, among which MMP‐1 was predominant in SCLC tissues and was inversely expressed with TFPI‐2 in 35% of cases. These results suggest that downregulation of TFPI‐2 expression could favour the development of SCLC.

Recurrent primary cutaneous mucinous carcinoma with neuroendocrine differentiation: case report and review of the literature

We report the case of a 60‐year‐old woman presenting with primary cutaneous mucinous carcinoma (PCMC) with neuroendocrine differentiation, revealed by neuroendocrine tumor lymph node metastasis 7 years before identification of the skin tumor. Only five cases of PCMC with neuroendocrine differentiation have been reported to date. The frequency of this neuroendocrine component may be underestimated, as it can require immunohistochemistry for identification, rather than being obvious on initial histopathologic examination. In the case presented here, the prominent neuroendocrine component displayed the morphological features of a well‐differentiated neuroendocrine tumor with expression of common neuroendocrine markers, strong expression of estrogen and progesterone receptors and low Ki67 proliferation index (5%). This case shows that not all primary cutaneous neuroendocrine carcinomas are Merkel cell carcinomas (MCCs). In addition to rare primary cutaneous carcinoid tumors, the diagnosis of PCMC with neuroendocrine differentiation must be considered, particularly when confronted by a mucinous tumor or lymph node metastases of neuroendocrine carcinoma of unknown origin. On the basis of this case, identification of a neuroendocrine component in a PCMC might be an adverse prognostic indicator of recurrence or of lymph node metastasis and should support wider excision margins of the tumor.

Professional Practices and Diagnostic Issues in Neuroendocrine Tumour Pathology: Results of a Prospective One-Year Survey among French Pathologists (the PRONET Study)

Introduction: Many changes have recently occurred in the practice of neuroendocrine tumour (NET) pathology. We therefore aimed to evaluate how pathologists have adapted their daily practice to the most recent international guidelines for diagnostic and prognostic evaluation. Procedures: A 12-month prospective study (PRONET) was carried out among French pathologists between August 2010 and July 2011. Data were collected using an anonymous electronic case report form. Observations: Five hundred laboratories were invited, 149 accepted to participate, 80 were active and 59 provided eligible cases. A total of 1,340 cases were collected. The primary tumour was gastroenteropancreatic in 58.1% of cases and thoracic in 18.1%; it was from another site in 9.7%; 12.3% of cases were metastases of unknown origin. Pathological diagnosis was made from the examination of surgical samples in 58.1% of cases, biopsy specimens in 33.5%, endoscopic resections in 3.1% and cytological preparations in 4.2%. For the demonstration of the neuroendocrine nature of the tumour, chromogranin A and synaptophysin were tested in, respectively, 97.1 and 82.8% of cases. The differentiation status was definitely provided in 95.7% of cases. Mitotic count was attempted in 80.1% of cases and Ki67 index in 80.7%. In gastroenteropancreatic (GEP)-NETs, histological grading was available in 95.9% of the cases. WHO classification was available or feasible in 94.1% of GEP-NETs and 93.8% of thoracic NETs. TNM staging was performed according to International Union against Cancer in 74.8% of GEP-NETs and according to European Neuroendocrine Tumour Society in 55.6%. Conclusions: The PRONET study shows that the current recommendations and diagnostic procedures are satisfactorily respected by most pathologists in daily practice.

Merkel cell carcinomas infiltrated with CD33+ myeloid cells and CD8+ T cells are associated with improved outcome

Background: Merkel cell carcinoma (MCC) is a rare tumor of the skin that has an aggressive behavior. Immunity is the main regulator of MCC development, and many interactions between lymphocytes and tumor cells have been proven. However, the impact of tumor‐infiltrating myeloid cells needs better characterization. Objective: To characterize tumor‐infiltrating myeloid cells in MCC and their association with other immune effectors and patient outcome. Methods: MCC cases were reviewed from an ongoing prospective cohort study. In all, 103 triplicate tumor samples were included in a tissue microarray. Macrophages, neutrophils, and myeloid‐derived suppressor cells were characterized by the following markers: CD68, CD33, CD163, CD15, CD33, and human leukocyte antigen‐DR. Associations of these cell populations with programmed cell death ligand 1 expression, CD8 infiltrates, and vascular density were assessed. Impact on survival was analyzed by log‐rank tests and a Cox multivariate model. Results: The median density of macrophages was 216 cells/mm2. CD68+ and CD33+ macrophage densities were associated with CD8+ T‐cell infiltrates and programmed cell death ligand 1 expression. In addition, MCC harboring CD8+ T cell infiltrates and brisk CD33+ myeloid cell infiltrates were significantly and independently associated with improved outcomes (recurrence‐free and overall survival). Limitations: Sampling bias and the retrospective design were potential study limitations. Conclusion: Infiltration of CD33+ myeloid cells and CD8+ T lymphocytes defines a subset of MCC associated with improved outcome.

Differentiating Merkel cell carcinoma of lymph nodes without a detectable primary skin tumor from other metastatic neuroendocrine carcinomas: The ELECTHIP criteria

Background: Merkel cell carcinoma (MCC) can present as a cutaneous tumor or a lymph node metastasis without a primary tumor. MCC presenting without a primary tumor (MCCWOPT) can be misinterpreted on histologic examination as lymph node metastasis (LNM) from another neuroendocrine carcinoma (LNMNEC). However, this distinction is crucial for therapeutic management. Objective: To determine the discriminative criteria for the differential diagnosis of MCCWOPT, LNM from cutaneous MCC, and LNMNECs. Methods: Clinical, morphologic, and immunohistochemical data (expression of cytokeratins AE1, AE3, 7, 19, and 20; chromogranin A, synaptophysin, thyroid transcription factor‐1 [TTF‐1]), as well as the presence of Merkel cell polyomavirus (by immunohistochemistry and PCR) were compared in patients with MCCWOPT (n = 17), LNM from a cutaneous MCC (n = 11), and LNMNEC (n = 20; 8 lung, 7 thyroid, 3 digestive tract, 2 other). Results: MCC (including MCCWOPT and LNM from a cutaneous MCC) differed from LNMNEC by 7 discriminative criteria: 1) elderly age, 2) location of the tumor, 3) extent of the disease, 4) cytokeratin expression, 5) TTF‐1 expression, 6) histologic type, and 7) Merkel cell polyomavirus detection, summarized under the acronym ELECTHIP. All MCC patients had ≥5 of the ELECTHIP criteria, whereas all patients with LNMNEC (except 1) had <3 criteria. Limitations: The discriminant ability of the ELECTHIP criteria should be validated in a second independent set. Conclusion: MCCWOPT can be distinguished from other LNMNEC by the ELECTHIP criteria.