SDHC and gastrointestinal stromal tumor: An observational study evaluated the clinical and molecular features of KIT/PDGFRA WT-GISTs in a cohort (patients < 19 y with GIST or > 19 y with WT-GIST), which was characterized by IHC for SDHB, sequencing of SDH genes, determination of SDHC promoter methylation, as well as germline testing of SDH genes for some of them (consented).