Additional markers exhibited in GIST such as CD34 (60%–70%), PKC-theta (90%), caldesmon (60%–80%), smooth muscle actin (SMA) (30%–40%), S-100 (5%), and desmin (1%–2%) can support diagnosis, but their expression varies by tumor location and they lack the specificity of CD117 or DOG1. This evidence concerns the gene KIT and gastrointestinal stromal tumor.