**6. Conclusion**

Since major advancement had been achieved in the field of molecular monitoring, molecular MRD analyses became widely incorporated into the clinical routine and the decision making-process. PCR is currently used in our clinical practice in patients expressing specific molecular targets undergoing both autologous and allogeneic HSCT. Post-transplant molecular monitoring is of twofold significance: predicting impending relapse and guiding future MRD-based decisions and treatment strategies. In patients undergoing allogeneic HSCT, MRD should be evaluated within a month prior to the start of the conditioning regimen. During the follow-up period, MRD should be monitored every three months in a BM sample for at least two years and according to individual risk thereafter. MRD status itself is not a conclusive or a sufficient criterion to decide to intervene therapeutically. The main inquiry remains whether, when and at what thresholds a clinical intervention is required. Welldesigned prospective clinical trials are needed to provide answers to these questions and establish MRD- guided clinical protocols.
