BRAF and KIT somatic mutations are present in amelanotic melanoma

Melanoma Res. 2013 Oct;23(5):414-9. doi: 10.1097/CMR.0b013e32836477d4.

Abstract

The genotypic profile of rare amelanotic melanomas (AMs) has been poorly investigated, thus preventing either an accurate identification as a distinctive melanoma subtype or therapy stratification. Here, we investigated the presence of the BRAF(V600E) mutation by real-time quantitative PCR and KIT mutations (exons 11 and 17) by sequencing analysis in 33 AMs. AMs included 'truly' amelanotic lesions (n = 19), with no melanin pigmentation upon dermoscopic inspection and hypomelanotic lesions (n = 14), by definition partially pigmented lesions showing a melanin pigmentation area of less than 25% of the total surface area. The frequency of the BRAF(V600E) mutation was 70.3% in the 33 cases, a percentage that increased to 89% when only the subgroup of thin melanomas (≤ 1 mm in thickness, n = 9) was considered. KIT mutations were found in 12.1% of AMs, all of which developed in nonacral sites. The identification of a relatively high frequency of BRAF(V600E) and KIT mutations in AMs may have important consequences for implementation of the novel targeted therapies now available to treat this life-threatening disease.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / genetics*
  • DNA Mutational Analysis / methods
  • Female
  • Gene Frequency
  • Genetic Predisposition to Disease
  • Humans
  • Italy
  • Male
  • Melanoma, Amelanotic / enzymology
  • Melanoma, Amelanotic / genetics*
  • Melanoma, Amelanotic / pathology
  • Middle Aged
  • Mutation*
  • Phenotype
  • Proto-Oncogene Proteins B-raf / genetics*
  • Proto-Oncogene Proteins c-kit / genetics*
  • Real-Time Polymerase Chain Reaction
  • Retrospective Studies
  • Risk Factors
  • Skin Neoplasms / enzymology
  • Skin Neoplasms / genetics*
  • Skin Neoplasms / pathology

Substances

  • Biomarkers, Tumor
  • Proto-Oncogene Proteins c-kit
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf