Variations on a theme: the alternate translocations in APL

The t(15;17)(q22;q21) translocation is tightly linked to the APL phenotype, and the resultant PML-RAR fusion can be demonstrated in 98% of APL cases. Rare variant translocations have been reported, the majority of which on detailed analysis represent cryptic PML-RAR fusions. However, a handful of APL cases have been described with different genotypes. These include the t(11;17)(q23;q21) that produces the PLZF-RAR fusion, t(5;17)(q35;q21) that forms NPM-RAR, t(11;17)(q13;q21) that generates NUMA-RAR, and der(17) that creates STAT5b-RAR. In this review we will discuss these variant translocations, and discuss the insights that we have gained from their study.