In Situ Point Mutation Detection in FFPE Colorectal Cancers Using the BaseScope Assay.

In situ mutation detection (ISMD) is a powerful tool for the characterization of tumor heterogeneity at cellular resolution while preserving tissue morphology and spatial context. The BaseScope assay is a novel approach to ISMD, offering excellent specificity and sensitivity, with little requirement for assay optimization or technical expertise. Here we describe the validation and application of BaseScope ISMD probe sets to human formalin-fixed paraffin-embedded (FFPE) samples, firstly by testing the probes in well-characterized cell lines of known mutational status, and then by applying the assay to archival FFPE colorectal cancers.