Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to retinoblastoma ?
    ### Response:
    Mutations in the RB1 gene are responsible for most cases of retinoblastoma. RB1 is a tumor suppressor gene, which means that it normally regulates cell growth and keeps cells from dividing too rapidly or in an uncontrolled way. Most mutations in the RB1 gene prevent it from making any functional protein, so it is unable to regulate cell division effectively.
    