Working with colleagues at the University of Rochester School of Medicine, Harvard researchers found that giving mice a hormone known for building bones increased their production of blood stem cells. If it works in humans as in mice, the advance could provide additional hope for patients suffering from leukemia, myeloma, or lymphoma who need bone marrow transplants. The researchers, largely based at Massachusetts General Hospital’s (MGH) Center for Regenerative Medicine and Technology, have begun setting up a phase 2 trial to test their findings in human subjects. They predict the trial will begin early next year. Associate Professor of Medicine David Scadden, director of MGH’s Center for Regenerative Medicine and Technology, and his colleagues’ research indicated that, coupled with parathyroid hormone treatments, it may be possible to use fewer stem cells in a transplant. That would make transplants with fewer cells, as would occur in the use of umbilical cord cells, a safer procedure. Whatever the case, either having more stem cells available for transplant or needing fewer would benefit patients, Scadden said. The study was published in the Oct. 23, 2003 issue of the journal Nature.