KIT and gastrointestinal stromal tumor: In addition, the global DNA hyper-methylation associated with the SDH-deficient GIST has been shown to mediate insulator losses and topological reorganisation of the Fibroblast Growth Factor (FGF) and KIT loci which leads to induction of the FGF4 and FGF3 oncogenes and sensitivity to FGF receptor (FGFR) inhibition [47].