NPM1 and acute myeloid leukemia: Our data suggests MRCH as a feasible marker for MRD assessment in AML patients after allogeneic HSCT, with comparable clinical value as the standard MRD marker NPM1. Subsequently, evaluation of MRCH may be a valuable clinical tool to detect relapse early after allogeneic HSCT, especially in patients lacking or loosing conventional MRD markers such as NPM1. When confirmed, MRCH can aid in guiding preemptive treatment decisions to improve outcomes after HSCT.