STAT5B and acute promyelocytic leukemia: All of the 6 atypical APL have corresponding chromosome translocation as follows: t(11,17) (q23,q21), t(11,17)(q13,q21), t(5,17)(q35,q21), t(4,17)(q12,q21), t(X,17)(p11,q21), and 17q.[1,6–9] We have known that PML-RARα, NuMA-RARα, NPM-RARα are sensitive to ATRA, but both PLZF-RARα and STAT5b-RARα are insensitive.[7,10] Here we will report 3 cases of atypical APL with the clinical feature, treatment and the outcome.