Dideoxy sequencing enhances detection of KIT mutations in GISTs initially evaluated by NGS hotspot panels

GISTs are predominantly characterized by mutations in KIT or PDGFRA. Mutation detection is important for optimal therapy. NGS panels are useful in GIST assessment as they allow for simultaneous evaluation of multiple genes. However, inherent to use of NGS with short read sequences on formalin-fixed specimens is the potential to miss larger indel variants. Over nine years, GIST testing was performed on specimens from 55 patients by amplicon-based, semi-conductor NGS using the Ion AmpliSeq Cancer Hotspot Panel v2 (CHPv2), a CHPv2-based GIST panel, or the Oncomine Precision Assay.