Expanding uses of high-dose factor VIIa

been detected in small fractions of uncommitted and lineage-committed hematopoietic progenitor cells, but the functional role of WT1 in the development and regulation of the normal hematopoiesis is currently not well characterized. Further, constitutive expression of wild-type or mutant WT1 has been demonstrated in a variety of hematologic malignancies and, particularly, in blasts of nearly all acute leukemias irrespective of lineage-specificity. Therefore, WT1 expression may be regarded as a nonspecific “panleukemic” molecular marker, and quantitative monitoring of WT1 transcripts holds promise to become a universal tool for the evaluation of MRD after chemotherapy or HSCT, especially for the approximately 50% of acute leukemias without an established disease-specific gene rearrangement. This expectation is further promoted by the work of Ogawa and coworkers (page 1698), which strongly supports that sequential analyses of WT1 transcript expression levels in marrow cells after allogeneic HSCT can be used to reliably predict leukemic relapse and responses to immunomodulatory interventions against imminent or overt posttransplantation relapse. If confirmed by larger prospective studies, this work would substantially contribute to close the diagnostic gap of MRD detection and to define universal MRD thresholds for clinical decision-making after HSCT. —Dietrich W. Beelen University of Essen, Germany