👉 Leukemia is a type of cancer that occurs in the blood and other tissues. It usually starts in the bone marrow, which is the part of the body where red blood cells are made. Leukemia can cause damage to these cells, making it difficult for them to produce enough red blood cells or other blood cells. This can lead to a variety of symptoms, including fatigue, weakness, and bleeding. Treatment for leukemia depends on the type of leukemia and the stage of the cancer.