Leukemias are a group of cancers that affect the blood and bone marrow, leading to the overproduction of abnormal white blood cells. These cells do not function properly, which can weaken the immune system and hinder the body's ability to fight infections. There are several types of leukemia, including acute lymphoblastic leukemia (ALL) and chronic myeloid leukemia (CML), each with different characteristics and treatment approaches. Symptoms of leukemia can include fatigue, frequent infections, easy bruising or bleeding, and unexplained weight loss. Diagnosis typically involves blood tests and bone marrow examinations. Treatment options may include chemotherapy, radiation therapy, and stem cell transplants, depending on the specific type and stage of the disease.