Update in Molecular Diagnostics in Melanocytic Neoplasms
*Department of Dermatology †Robert H. Lurie Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL. Advances in anatomic pathology
(Impact Factor: 3.23).
11/2012; 19(6):410-6. DOI: 10.1097/PAP.0b013e318271a5cb
Future classification systems for melanocytic neoplasms will likely include the integration of molecular aberrations. A number of studies have shown that many gene mutations and chromosomal copy number aberrations may correlate with characteristic clinical and morphologic features for melanocytic neoplasms. This review discusses newly described familial germline mutations such as the BRCA1-associated protein-1 familial melanoma syndrome, recently described somatic mutations, and chromosomal copy number aberrations recently described in melanoma. Further, we discuss how these specific molecular aberrations correlate with specific clinical and morphologic features in melanocytic neoplasm and their implications for prognosis and molecular diagnostics. In addition, we discuss state of the art advancements in molecular diagnostics for melanocytic neoplasms and newly developed fluorescence in situ hybridization assays including the utility of fluorescence in situ hybridization for 9p21 in spitzoid melanocytic neoplasms. Lastly, we discuss a phenomenon known as paradoxical activation of wild-type BRAF seen in patients treated with vemurafenib and some potential clinical presentations of this process.
Available from: Xu Dong Zhang
- "This is important, as the molecular alterations are associated with intracellular signaling pathway changes, clinical features, and responses to different treatment regimes. Molecular diagnosis could be included in the routine diagnosis for melanoma in the near future.103 More and more newly developed techniques are used in the molecular diagnosis of melanoma, such as tissue array, proteomics, and DNA sequencing.104 "
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ABSTRACT: Melanoma is the most aggressive type of skin cancer and has very high rates of mortality. An early stage melanoma can be surgically removed, with a survival rate of 99%. However, metastasized melanoma is difficult to cure. The 5-year survival rates for patients with metastasized melanoma are still below 20%. Metastasized melanoma is currently treated by chemotherapy, targeted therapy, immunotherapy and radiotherapy. The outcome of most of the current therapies is far from optimistic. Although melanoma patients with a mutation in the oncogene v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) have an initially higher positive response rate to targeted therapy, the majority develop acquired drug resistance after 6 months of the therapy. To increase treatment efficacy, early diagnosis, more potent pharmacological agents, and more effective delivery systems are urgently needed. Nanotechnology has been extensively studied for melanoma treatment and diagnosis, to decrease drug resistance, increase therapeutic efficacy, and reduce side effects. In this review, we summarize the recent progress on the development of various nanoparticles for melanoma treatment and diagnosis. Several common nanoparticles, including liposome, polymersomes, dendrimers, carbon-based nanoparticles, and human albumin, have been used to deliver chemotherapeutic agents, and small interfering ribonucleic acids (siRNAs) against signaling molecules have also been tested for the treatment of melanoma. Indeed, several nanoparticle-delivered drugs have been approved by the US Food and Drug Administration and are currently in clinical trials. The application of nanoparticles could produce side effects, which will need to be reduced so that nanoparticle-delivered drugs can be safely applied in the clinical setting.
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ABSTRACT: We recently reported three cases of metastatic melanoma that does not express S100, HMB45, Melan A and Tyrosinase. A concurrent cutaneous scalp primary melanoma was identified later in one of the cases, which showed strong expression of these markers. The difference in immunophenotype between the primary melanoma and its metastasis in the parotid gland in this case raised the question of the biological significance of the expression of these markers and metastatic potential. To address this question, we utilized microarray comparative genomic hybridization (aCGH) to compare the cytogenetic features between the primary and metastatic melanoma. We observed chromosomal gains including 6p, entire chromosome 7, and 8q11.1-q24.3 in both primary and metastatic tumors. However, the metastatic lesion showed unique additional copy of chromosomal 7q, and loss of chromosome 9p24.3-q13 and chromosome 4, which included Melan A encoding gene region in 9p24.1. The above findings suggest the unique cytogenetic changes in the parotid lesion are most likely related to the metastatic behavior, as well as responsible for loss of multiple melanocytic marker expression in the metastatic melanoma for this case.
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ABSTRACT: Fluorescent in situ hybridization (FISH) and comparative genomic hybridization (CGH) are molecular techniques that have become valuable adjuncts in the diagnosis of histopathologically ambiguous melanocytic tumors. These techniques detect the presence of chromosomal gains or losses that are characteristic of malignant transformation in melanocytic neoplasms. CGH and FISH have been used to characterize distinct genomic characteristics of melanocytic tumors at various anatomic sites and tumors with certain histopathologic features (e.g. spitzoid, blue nevus-like, congenital nevi). Recent developments in this field include the transition of CGH from a research tool to a clinically available test and a new FISH probe set targeting chromosomal loci 11q13, 8q24, 6p25 and 9p21 that reportedly distinguishes melanoma from melanocytic nevi with a sensitivity and specificity of 94% and 98% respectively. Genomic analysis of melanocytic tumors also provides prognostic information. This review discusses these new advances in molecular diagnostics in melanoma and future directions in the field.
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