Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the symptoms of Gastrointestinal Stromal Tumors ?
    ### Response:
    Signs of gastrointestinal stromal tumors include blood in the stool or vomit. These and other signs and symptoms may be caused by a GIST or by other conditions. Check with your doctor if you have any of the following:         -  Blood (either bright red or very dark) in the stool or vomit.
    