Hematopoietic stem cell transplantation is a curative treatment for a number of benign and malignant hematologic diseases. One of the key parts of hematopoietic stem cell transplantation is the prophylaxis of graft-versus-host disease. Since the end of the 1970s, with the introduction of cyclosporine, calcineurin inhibitors (cyclosporine and tacrolimus) have become part of almost all prophylactic regimens, even though they are a group of drugs with a poor toxicity profile that requires monitoring. constant serum level. Since 2008, post-transplant cyclophosphamide has been introduced with great success, associated with a calcineurin inhibitor and mycophenolate, in the prophylaxis of graft-versus-host disease in haploidentical transplantation (50% matched). Since then, in view of this enormous success, efforts have been made to incorporate post-transplant cyclophosphamide in matched related and unrelated transplants, or with a mismatch. This is a prospective, 2-arm, non-randomized study. Arm 1, with related donors, and arm 2, with unrelated donors. Patients will be allocated in these arms according to donor availability (patients with a matched-sibling donor will receive a matched-sibling transplant; patients with no related donors but with unrelated donors, an unrelated transplant). Patients who are ready for transplantation with matched-sibling or unrelated donors will be recruited to participate in the study. The stem cell collection target will be 5E6 CD34/kg recipient weight for peripheral source. If a quantity greater than this is collected, the remainder will be cryopreserved according to the institutional protocol. Graft-versus-host disease prophylaxis will be performed on D+3 and D+4 with cyclophosphamide and with ATG on D-3 and D-2 for matched-sibling or unrelated donors transplants.