Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Childhood Brain Stem Glioma ?
    ### Response:
    Key Points 
                    - Childhood brain stem glioma is a disease in which benign (noncancer) or malignant (cancer) cells form in the tissues of the brain stem.    - Brain tumors may be benign (not cancer) or malignant (cancer).     - There are two types of brain stem gliomas in children.
    