Melanocytic nevi excised during B-Raf proto-oncogene (BRAF) inhibitor therapy: A study of 19 lesions from 10 patients

The nevi associated with BRAF inhibitor therapy invariably lack BRAFV600E mutation. BRAF inhibition appears to cause an increased cytotoxic T-cell response and increased mitogen-activated protein kinase activity in BRAF wild-type lesions, supported by pERK expression, possibly resulting in an activated phenotype characterized by increased melanin pigmentation and deep HMB-45 expression.