Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Childhood Central Nervous System Germ Cell Tumors ?
    ### Response:
    Key Points
                    - Childhood central nervous system (CNS) germ cell tumors form from germ cells.     - There are different types of childhood CNS germ cell tumors.          - Germinomas     - Nongerminomas        - The cause of most childhood CNS germ cell tumors is not known.
    