RATIONALE: Giving chemotherapy and total-body irradiation before a donor bone marrow transplant helps stop the growth of cancer cells. It also helps stop the patient's immune system from rejecting the donor's stem cells. When the stem cells from a related or unrelated donor, that closely matches the patient's blood, are infused into the patient they may help the patient's bone marrow to make stem cells, red blood cells, white blood cells, and platelets.