Blood taken from newborns' umbilical cords appears to offer a good source of lifesaving tissue for cancer victims and others who likely would die without bone marrow transplants but do not have related donors.

The largest study yet of transplants using cord blood for patients who have no related donors shows a lessened risk of potentially fatal reactions that can result when people get marrow from donors whose tissue types are not closely matched. Transplants were considered successful for 4 of 5 patients.

Marrow transplants are a standard part of cancer treatment. In an attempt to kill cancer, doctors often give such high doses of chemotherapy that they also destroy the bone marrow, which manufactures blood cells. So they replace it with blood-producing cells, called stem cells, that are taken from donors.