BRAF Mutation Is Associated With the Unique Morphology of Traditional Serrated Adenoma of the Colorectum

Traditional serrated adenoma (TSA) consists of glands with tall cells and short cells. Two kinds of cells alternate to give a unique serrated configuration. The aim of this study was to identify the relationship between the alterations of both Wnt and serrated pathways and the unique morphology of TSAs. The tall and short cells in 28 TSAs were separated by microdissection. Semi-nested polymerase chain reaction was performed to detect the mutations of BRAF, -catenin, APC, and KRAS. BRAF mutations were observed in 22 of 28 (78.6%) TSAs, and all mutations occurred at the tall cells. In conclusion, BRAF mutation is associated with the serrated morphology of TSAs. Genetic alterations in both the serrated pathway and the Wnt signaling pathway may both contribute to TSAs.