Test Details: Immunohistochemical testing is carried out on biopsy/resected tissue specimen. This testing helps to identify specific antigens (proteins) within tissue sections utilizing an antigen-specific antibody. DOG-1 (anoctamin-1) is a transmembrane chloride channel protein highly expressed in the cells of Cajal of the gastrointestinal tract. DOG-1 is a highly specific marker for gastrointestinal stroma tumours (GISTs) and stains few salivary gland tumours.