Postoperative immunohistochemical profiling confirmed classic GIST immunophenotype with CD117(+), DOG1(+), CD34(+), SDH-a(+), SDH-β(+), Desmin(-), H-cal desmon(-), S-100(-), SHA(-), and Ki-67 (4%) (Figures 2C–E). The gene discussed is SDHB; the disease is gastrointestinal stromal tumor.