NPM1 and acute myeloid leukemia: WT1 mRNA is overexpressed at least 80% of patients with AML and can be universally used as an MRD marker, even in patients with AML who are not eligible for leukemia-specific polymerase chain reaction (PCR) assays (e.g., for NPM1, PML-RARA, or CBF AML) [11, 12].