Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Gastrointestinal Carcinoid Tumors ?
    ### Response:
    Key Points
                    - A gastrointestinal carcinoid tumor is cancer that forms in the lining of the gastrointestinal tract.     -  Health history can affect the risk of gastrointestinal carcinoid tumors.     - Some gastrointestinal carcinoid tumors have no signs or symptoms in the early stages.
    