Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Multiple myeloma ?
    ### Response:
    Multiple myeloma is a form of cancer that occurs due to abnormal and uncontrolled growth of plasma cells in the bone marrow. Some people with multiple myeloma, especially those with early stages of the condition, have no concerning signs or symptoms. When present, the most common symptom is anemia, which can be associated with fatigue and shortness of breath.
    