What is Leukemia? Symptoms, Causes, and Treatment

Leukemia is a type of blood cancer that affects the white blood cells responsible for fighting off infections. There are four main types of leukemia—acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), acute myeloid leukemia (AML), and chronic myeloid leukemia (CML). Symptoms of ALL and AML include frequent infections, fatigue, and unexplained weight loss. CLL and CML may not show any symptoms in the early stages.