Esophageal melanomas harbor frequent NRAS mutations unlike melanomas of other mucosal sites

Virchows Arch. 2009 May;454(5):513-7. doi: 10.1007/s00428-009-0762-6. Epub 2009 Mar 25.

Abstract

Mucosal melanomas have genetic alterations distinct from those in cutaneous melanomas. For example, NRAS- and BRAF-activating mutations occur frequently in cutaneous melanomas, but not in mucosal melanomas. We examined 16 esophageal melanomas for genetic alterations in NRAS, BRAF, and KIT to determine whether they exhibit genetic features common to melanomas arising from other mucosal sites. A sequencing analysis identified NRAS mutations in six cases; notably, four of these mutations were located in exon 1, an uncommon mutation site in cutaneous and other mucosal melanomas. BRAF and KIT mutations were found in one case each. Immunohistochemistry showed KIT expression in four cases, including the tumor with a KIT mutation and two other intramucosal tumors. The low frequency of BRAF mutations and the presence of a KIT mutation-positive case are findings similar to those of mucosal melanomas of other sites, but the prevalence of NRAS mutations was even higher than that of cutaneous melanomas. The present study implies that esophageal melanomas have genetic alterations unique from those observed in other mucosal melanomas.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Cytosine / metabolism
  • DNA Mutational Analysis
  • DNA, Neoplasm / genetics
  • Esophageal Neoplasms / genetics*
  • Esophageal Neoplasms / pathology
  • Female
  • Guanine / metabolism
  • Humans
  • Male
  • Melanoma / genetics*
  • Melanoma / pathology
  • Middle Aged
  • Mucous Membrane / pathology
  • Mutation*
  • Proto-Oncogene Proteins B-raf / genetics
  • Proto-Oncogene Proteins B-raf / metabolism
  • Proto-Oncogene Proteins c-kit / genetics
  • Proto-Oncogene Proteins c-kit / metabolism
  • ras Proteins / genetics*
  • ras Proteins / metabolism

Substances

  • DNA, Neoplasm
  • Guanine
  • Cytosine
  • Proto-Oncogene Proteins c-kit
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf
  • ras Proteins