FLT3 and acute myeloid leukemia: Furthermore, our data suggest that the NUP98::NSD1 fusion co-occurs with FLT3-ITD and worsens the prognosis of FLT3-ITD positive patients independent of FLT3-ITD allelic ratio; hence it should be routinely screened in all FLT3-ITD-positive AML patients, as it has important treatment ramifications.