<prompt> Which of the following markers is specific for gastro-intestinal stromal tumor GIST -CD117CD34CD23S-100  <response>: ImmunohistochemistryFollowing markers are present in GISTs:CD 117 c kit 95CD 34 70Smooth muscle actin 5CD 117 c kit is considered the most specific markerCD 117 c kit immunoreactivity is the best defining feature of GISTs distinguishing them from true smooth muscle tumors leiomyoma and tumors arising from neural crest.Although CD 117 c kit is considered the most specific marker for GIST, it is not pathognomonic of GIST as other tumors may also express CD 117. These tumors include mast cell tumor, germ cell tumors seminomas, leukemias, malignant melanoma, angiolipomas, and some sarcomas. 