Many cases of CTCF disruption have been associated with changes in DNA methylation such as in isocitrate dehydrogenase (IDH) mutant gliomas [21], succinate dehydrogenase (SDH)-deficient gastrointestinal stromal tumors (GIST) [22], and immunoglobulin or T cell receptors [18]. The gene discussed is IDH3A; the disease is gastrointestinal stromal tumor.