WT1 and leukemia: Pioneered by the group of Sugiyama et al. in the early nineties and still broadly explored in Japan, quantification of the levels of WT1 transcripts using qRT-PCR showed a correlation between the WT1 mRNA and occurrence of relapse in leukemia patients with MRD after chemotherapy or allogeneic transplantation, and the authors proposed WT1 mRNA expression levels to be a “panleukemic MRD marker” [16, 17].