<qa>  What type of cancer is there?Allogeneic hematopoietic stem cell transplantation or allotransplant; donor blood stem cells have been used with varying degrees of success as an immune therapy for blood-system cancers leukemias, myelodysplastic syndrome, lymphomas, multiple myeloma, etc.. Some people s cancer remains active comes back or continues to spread after an allotransplant, while other people s cancer disappears and they are hopefully cured . NIH researchers are studying the reasons for these different treatment outcomes, and trying to develop better cancer treatments for people with active cancer after allotransplant. Researchers are collecting data from people who have had allotransplants for a cancer of the blood, whether or not the cancer is in remission, and from their donors. Those with active cancers may be eligible to participate in one of several NIH studies testing treatments for active cancer after allotransplant. 