NPM1 and acute promyelocytic leukemia: Rarely, about 2% of APL is characterized by atypical rearrangements with PLZF, NPM1, NUMA, STAT5B, FIP1L1, PRKAR1A, BCOR, OBFC2A, TBLR1, GTF2I, IRF2BP2, FNDC3B, TFGA, NUP98, TNRC18, STAT3 and TFG (3, 4).