Four-year cumulative estimates of molecular relapse (left panel) and cytogenetic relapse (right panel) after transplantation of allogeneic bone marrow (BMT) or peripheral blood stem cells (PBSCT) in patients with first chronic phase CML. Molecular relapse was defined as two consecutive M-bcr-abl-positive PCR assays within a 4-week interval. Cytogenetic relapse was defined as reappearance of Philadelphia (Ph1) chromosome-positive marrow metaphases after transplant. Tick marks indicate patients who survive in continuous molecular (left panel) or cytogenetic (right panel) remission of CML.