Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Pituitary Tumors ?
    ### Response:
    Key Points
                    - A pituitary tumor is a growth of abnormal cells in the tissues of the pituitary gland.    - The pituitary gland hormones control many other glands in the body.    - Having certain genetic conditions increases the risk of developing a pituitary tumor.
    