PML and acute promyelocytic leukemia: For the seven APL samples (APL1, APL2, APL3, APL4, NB4s1, NB4s2, and NB4c) with known chromosomal translocation in the breakpoint cluster region (bcr), we identified three fusion junctions from PML to RARA and one fusion junction from RARA to PML (Fig. 4d).