A stem cell transplant is a medical procedure in which diseased bone marrow is replaced by highly specialized cells, called hematopoietic stem cells. Hematopoietic stem cells are found both in the bloodstream and in the bone marrow. Today, this procedure is more commonly called a stem cell transplant, rather than bone marrow transplant, because it is the blood stem cells that are typically being transplanted, not the actual bone marrow tissue.Before recommending transplantation, doctors will talk with the patient about the risks of this treatment and consider several other factors, such as the type of cancer, results of any previous treatment, and the patient’s age and general health.