Bone marrow is a soft, spongy tissue present inside the bone. The marrow possess stem cells, which are immature blood cells that are responsible for forming all kind of cells in the body of an individual.

The transplantation of bone marrow is necessary in the treatment of some kind of lymphomas. This is because extremely high dose chemotherapy delivered to lymphoma patients not only kill cancer cells, but also end up killing bone marrow or stem cells as well. This, in turn, leads to deprivation of blood-forming cells and also limits the chances of survival of the patient.

This is the reason why sometimes bone marrow is extracted from the body of the patient and then transplanted back to the patient after chemotherapy. This is known as autologous stem cell transplant or autologous bone marrow transplant.