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Molecular Diagnostics for Melanoma

Volume 1102 of the series Methods in Molecular Biology pp 199-226

Date:

Chromosomal Copy Number Analysis in Melanoma Diagnostics

  • Jeffrey P. NorthAffiliated withDepartment of Dermatology, University of California San FranciscoDepartment of Pathology, University of California San Francisco
  • , Swapna S. VemulaAffiliated withDepartments of Dermatology and Pathology, University of California San Francisco
  • , Boris C. BastianAffiliated withDepartments of Dermatology and Pathology, University of California San Francisco

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Abstract

The majority of melanocytic neoplasms can be correctly diagnosed using routine histopathologic analysis. However, a significant minority of tumors have ambiguous histopathologic attributes that overlap between melanocytic nevi and melanoma. Ancillary tests that assist in distinguishing potentially lethal melanomas from benign melanocytic nevi with atypical histopathologic features are available, but still need refining.

Most melanomas have chromosomal copy number aberrations, frequently involving multiple chromosomes. With rare exceptions, such anomalies are not found in melanocytic nevi. This difference formed the basis to develop assays that can help distinguish melanoma from nevi by fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH). FISH can detect chromosomal copy number changes of a limited number of loci within individual cells. By contrast, CGH assesses copy number across the entire genome, but typically is performed on bulk cell populations so that copy number changes in individual cells or subpopulations of cells can go undetected. Both FISH and CGH have been used to provide genomic information in histopathologically ambiguous melanocytic tumors that can assist pathologists make correct diagnoses.

Key words

Fluorescence in situ hybridization FISH Comparative genomic hybridization CGH Molecular diagnostics Ambiguous melanocytic tumors Copy number changes