BRAF and GNAQ mutations in melanocytic tumors of the oral cavity

Abstract

Objective: The genetic factors participating in oral melanoma evolution have not been studied extensively. We aimed to analyze the prevalence of BRAF and GNAQ mutations in a series of oral melanocytic tumors, nevi, and melanomas.

Study design: The study group consisted of 4 melanomas and 10 nevi (6 intramucosal, 4 blue nevi). DNA was extracted from paraffin-embedded tissue sections, and mutations in GNAQ and BRAF were analyzed with the use of mass spectrometery.

Results: V600E point mutation was identified in the BRAF gene in 3 intramucosal nevi and in 2 melanomas. Only 1 blue nevus harbored the GNAQ209 mutation. None of the BRAF-positive samples harbored GNAQ mutations.

Conclusions: The finding of BRAF mutations in oral benign and malignant melanocytic lesions points to a potential initiating role of BRAF in malignant transformation, which may have important therapeutic implications as those with BRAF mutations may benefit from specific treatment using RAF inhibitors.