%0 Journal Article
%T Viral Etiology of Merkel Cell Carcinoma MCC) :Implications in Diagnosis, Prognosis, Therapy and Prevention SciDoc Publishers | Open Access | Science Journals | Media Partners
%A Farid Menaa
%J Clinical Dermatology & Research (IJCDR)
%D 2018
%R http://dx.doi.org/10.19070/2332-2977-150002e
%X Merkel cell carcinoma (MCC) is a rare and a highly aggressive skin cancer of neuroendocrine origin that is frequently associated with a poor prognosis, a clonal integration of a polyomavirus (MCPyV), and a high propensy for recurrence and metastasis; its incidence increases with age, immunodeficiency and sun exposure [2, 4, 5, 6, 8]. Importantly, cytokeratin 20 (CK20) is expressed in approximately 95% of MCC cases, MCPyV in about 80% of cases, and MCPyV is less common in CK20-negative MCC [6]. The disease progression could be evaluated by means of high numbers of mitoses, proliferation and survival of tumour cells as marked by Ki-67- and Bcl-2-staining, and infiltration of lymphatic vessels [12]. Moreover, a recent meta-analysis using random effects model revealed that there is an increased risk for second malignancies due to MCC (e.g. malignant melanoma) [9]. In fact, the origin of MCC is rather controversial, its pathogenesis (e.g. the molecular mechanisms underlying MCC development after MCPyV infection) remains unclear, and MCC seems to be a heterogenous entity with distinct subtypes [2, 3]. Indeed, while the presence of neurosecretory granules and expression of specific biomarkers (i.e. PGP 9.5, chromogranin A and several neuropeptides) has suggested that MCCs originate from one of the neurocrest derivatives, most probably Merkel cells, zurHausen et al. hypothesized that they could originate from early B cells since they commonly express. Terminal deoxynucleotidyl Transferase (TdT) and Paired Box Protein-5 (PAX5), which are restricted to pro/pre-B cells and pre-B cells when co-expressed under certain physiologic circumstances [3]. Interestingly, Merkel cell polyomavirus (MCPyV), identified in 2008 as a clear first causal agent underlying a human cancer, suggests that healthy human skin harbors resident or transient MCPyV critically capable of neoplastic transformation [7, 8]. In this context, MCPyV was recently classified as a 2A carcinogen based on a consensus staging system for MCCs adopted worldwide in 2010, which replaced anyone of the five unique systems in active use [7, 8]. The consensus system that includes sub-stages that reflect prognostic differences based on whether nodal evaluation was performed by histopathology analysis or clinical assessment alone, has improved the ability to track and manage this malignancy [7]. MCPyV, and MCC tumor cells express putative polyomavirus on coprotein small T antigen (sTAg) with robust transforming activity in-vivo as well as a truncated large T antigen (lTAg) [11, 13]. In patients who produce
%K n/a
%U https://scidoc.org/IJCDR-2332-2977-03-001e.php