SPI1 and acute promyelocytic leukemia: To assess if PU.1 modulates the expression of miR‐29b in non‐APL myeloid cells, Kasumi‐1 cells, bearing the t(8;21) chromosomal translocation, were treated with agonists known to upmodulate this transcription factor, stemming from the notion that, in this cell line, ectopic expression of PU.1 overcomes its functional block induced by AML1‐ETO.18