BRAF V600E ARMS-PCR. A, Four PCR primers are included in one PCR tube. Fo-Ro primer pair generates a common fragment of 200 bp flanking the mutation site. Fo-Rimut primer pair generates the 144 bp fragment specific to BRAF V600E. Fiwt-Ro primer pair generates a 97 bp fragment specific to wild-type BRAF. B, Sensitivity study. Agarose gel electrophoresis showed band pattern of a mixing study using BRAF V600E positive HT-29 cell DNA spiked into K-562 cell DNA at wide range of ratio namely 0, 0.1%, 0.25%, 0.5%, 1%, 2.5%, 5%, 10%, 20% and 50%. The assay can detect 0.5% BRAF V600E allele in a wild-type background. M, 100 bp DNA marker; BK, blank (no DNA) control.