A Novel Assay Coupling Dephosphorylation and Blue/White Colony Screening for the G > A Hotspot Mutation at Codon 13 of KRAS Gene

: Development of sensitive assay for detection of hotspot mutations of cancer driving gene is crucial for circulating tumor DNA analysis. This study tested the possibilities of applying restriction enzyme digestion and dephosphorylation coupled with blue/white screening technology for analyzing a hotspot point mutation in codon 13 of KRAS gene. The present study has documented that the combination of PCR with restriction digestion, dephosphorylation, blue/white screening and Sanger's sequencing can identify rare mutations with sensitivities at 0.003%. This novel assay with high sensitivity may have application in the diagnosis of early cancer targeting ctDNAs.