The reliability of ﬂow cytometric MRD assays depends on several factors. The most important being the correct marker combination in use. Applicability is limited in some cases by the lack of suitable leukemia associated immunophenotype (LAIP) with the currently used markers and also antigen immunomodulation post treatment. Therefore, the identiﬁcation of new leukemia markers that are easily detectable and are stably expressed in a large proportion of ALL cases should simplify the application of MRD studies, help extend their beneﬁt to all patients and possibly enhance the sensitivity of MRD detection.