A, Representative BRAF V600E ARMS-PCR results. Specimen 9, 26 and 32 had a low abundance of BRAF V600E mutation with band intensity similar to that of the 2.5% sensitivity control. Specimen 13 was strongly positive for BRAF V600E mutation. B, Direct dideoxy sequencing of specimen 9 failed to identify BRAF V600E mutation as the mutant allele burden was below the limit of detection. C, Direct dideoxy sequencing of specimens 13 showed that the mutant allele (A) was more abundant than the wild-type allele (T). D, H&E stain of specimens 9 and 13 showed that tumor areas accounted for ~15% and 50% of the total specimen areas, respectively.