Leukemia is a type of cancer that affects the blood and bone marrow, characterized by the uncontrolled production of abnormal white blood cells. These abnormal cells can interfere with the body's ability to produce healthy blood cells, leading to various health issues such as anemia and increased susceptibility to infections. There are several types of leukemia, including acute and chronic forms, which can affect both children and adults. Treatment often involves chemotherapy, radiation therapy, or stem cell transplantation.