Some experimental evidence indicates that uncommon BRAF mutations consisting in the substitution of 2 adjacent nucleotides within codon 600 are in a cis configuration and associate with BRAF gene amplification. These findings suggest that BRAFV600 mutations are unlikely to occur as homozygous alterations in clinical melanoma samples, with gene amplification perhaps contributing to mask the heterozygous state.
Keywords: BRAF; MHC; homozygosis; immunotherapy; melanoma; vemurafenib.