SDHB and gastrointestinal stromal tumor: Despite the frequent occurrence of lymph node and hepatic metastases, the disease course of SDH-deficient GISTs is often clinically indolent, pointing to the need for careful selection of therapy or watch-and-wait strategies in advanced disease.7, 9Generally, SDH-deficient GISTs are widely considered not sensitive to TKIs,18as all other KIT/PDGFRA WT GIST.