In fact, CpG dinucleotides located inside the FGF4 gene were hypomethylated in all GIST subgroups independent of FGF4 gene expression, which was higher in SDH-deficient and quadruple WT GISTs and was absent in KIT mutant GISTs (Fig. 1B). The gene discussed is FGF4; the disease is gastrointestinal stromal tumor.