This document discusses leukemia, including its symptoms, causes, types, diagnosis, and treatment. Leukemia is cancer of the blood or bone marrow that results in abnormal blood cell production. There are four main types of leukemia - acute lymphoblastic, chronic lymphocytic, acute myeloid, and chronic myeloid leukemia. Diagnosis involves blood tests, bone marrow biopsies, and other exams. Treatment depends on the type and phase of leukemia, and may include chemotherapy, targeted therapies, radiation, surgery, or stem cell transplants.