<prompt> Gastrin is a marker of which carcinoma?Medullary carcinoma of thyroidGISTGastric carcinomaPancreatic neuroendocrine tumor  <response>: Gastrinoma: Zollinger Ellison Syndrome: Marked hyper recreation of gastrin usually has its origin in gastrin- producing tumor, which are just as likely to arise in the duodenum and peripancreatic soft tissue as in pancreas so called gastrinoma triangle Gastrinoma is a type of pancreatic Neuro endocrine tumorPNET GI NET:- Gastrointestinal Neuro endocrine Tumor: PNET Carcinoid tumor Patient with MEN I syndrome have more chance of developing gastrinoma. - Medullary carcinoma of thyroid marker: Calcitonin. If patient have calcitonin negative medullary thyroid cancer most impoant tumor marker is CEA. - GIST- Mesenchymal tumor Origin: Cell of Cajal Pacemaker of GIT Vascular:- Bleeding Stomach Most specific tumor marker:- DOG-1CD 117CD 34 - Due to overactivity of tyrosine kinase enzyme DOC :- ImatinibTyrosine kinase Inhibitor 