CD34 may be positive in some leiomyosarcomas, but this is not a consistent feature, whereas most gastric GISTs are strongly positive for CD117, DOG1, and CD34, and variably express α-SMA [11]. The expression of h-caldesmon, a muscle-specific actin-binding protein, provides additional evidence of smooth muscle differentiation and helps distinguish leiomyosarcomas from GISTs [4]. The gene discussed is ACTA1; the disease is leiomyosarcoma.