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Updated: Jan 14, 2026

Spatial and Temporal Control of Murine Melanoma Initiation from Mutant Melanocyte Stem Cells
06:09

Spatial and Temporal Control of Murine Melanoma Initiation from Mutant Melanocyte Stem Cells

Published on: June 7, 2019

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Clinicopathogenomic Characteristics of Primary and Metastatic Melanomas With RAF1 and BRAF Fusions

Cecilia Lezcano1, Israel S Kasago2, Haiming Tang1,2

  • 1Dermatopathology, Department of Pathology and Laboratory Medicine.

The American Journal of Surgical Pathology
|October 17, 2025
PubMed

Insights

RAF1 and BRAF gene fusions drive rare melanomas, often in adults, and typically lack Spitz features. Understanding these fusion-positive melanomas is crucial for targeted therapy development.

Area of Science:

  • Oncology
  • Genetics
  • Dermatology

Background:

  • Mitogen-activated protein kinase (MAPK) pathway point mutations are common drivers in melanocytic neoplasms.
  • Gene fusions are less frequent oncogenic alterations in melanocytic tumors.
  • Kinase fusions characterize Spitz neoplasms, but not all fusion-driven melanomas fit Spitz criteria.

Purpose of the Study:

  • To characterize the clinical, histopathologic, and molecular features of RAF1 and BRAF fusion-positive melanomas.
  • To investigate the presentation and behavior of these rare melanoma subtypes.
  • To highlight the importance of recognizing these tumors for therapeutic strategies.

Main Methods:

  • Retrospective analysis of clinical data.
  • Histopathologic examination of tumor morphology.
  • Molecular profiling to identify RAF1 and BRAF gene fusions.

Main Results:

  • Identified 7 RAF1 and 23 BRAF fusion-positive melanomas.
  • Most tumors occurred in adult patients.
  • The majority of melanomas lacked Spitz-like microscopic features.
  • Patients presented with or developed regional/distant metastases.

Conclusions:

  • RAF1 and BRAF fusion-positive melanomas represent a distinct molecular subtype.
  • These tumors often present without typical Spitz features, challenging diagnosis.
  • Recognizing these fusion-positive melanomas is vital due to actionable therapeutic targets.
Keywords:
BRAFRAF1fusionmelanoma

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