SMN1 and gastrointestinal stromal tumor: Another study demonstrated the presence of spindle shaped smooth muscle-like cells in primary pancreatic leiomyosarcoma, and IHC markers SMA (+), MSA (+), Desmin (+), CD117 (-), HMB45 (-), DOG-1 (-), CD34 (-) [10], while gastrointestinal stromal tumors were characterized by CD117 (+), CD34 (+), DOG-1 (+), SMA (-), Desmin (-), S-100 (-) [11].