<s>[INST] <<SYS>> This is a medical question of type : information <</SYS>> What is (are) Chronic Myelogenous Leukemia ? [/INST] Chronic myelogenous leukemia is a disease in which too many white blood cells are made in the bone marrow. See the PDQ summary on Chronic Myelogenous Leukemia Treatment for information on diagnosis, staging, and treatment. </s>