PRRT2 and desmoid tumor: PKCθ was previously reported to be expressed in the interstitial cells of the Cajal lineage, Auerbach's plexus, T-cells, mast cells, endothelial cells, lymphoid organs, nervous system, skeletal muscle, and 72-100% of GISTs, without positivity for other c-KIT negative soft tissue tumors, desmoid tumors or carcinomas [6, 8–10, 14, 20].