The National Institutes of Health (NIH) has entered into a Transplant Center Participation Agreement with the National Marrow Donor Program (NMDP). This agreement allows any NIH investigator with an NIH Institutional Review Board (IRB) approved protocol to secure hematopoietic stem cells (HSC) or cord blood units from the NMDP/CIBMTR registry for the purpose of transplanting patients who have no suitable matched related donors. As part of this agreement, the NMDP/CIBMTR Research Program requires that blood samples as well as baseline and outcome data (mainly demographic, quality of life, and clinical data) be collected and maintained in accordance with the NMDP/CIBMTR IRB approved protocols. The goal of the NMDP/CIBMTR Research Program is to improve the safety and effectiveness of unrelated donor HSC transplantation for both the donors and recipients, and to have a comprehensive source of data that can be used to study unrelated donor HSC transplantation. The NMDP/CIBMTR is the sole custodian of the data in the Research Database.