Acute Promyelocytic Leukemia Cases With Nonreciprocal PML/RARαor RARa/PMLFusion Genes

Tumor-associated chromosome translocations usually lead to the formation of two reciprocal fusion genes: one thought to be involved in the transformation process, the other the mechanical consequence of the translocation event. In the case of acute promyelocytic leukemia (APL) blasts, the 15; 17 chromosome translocation generates the putatively transforming PML/RARafusion gene and its reciprocal RARa/PML.We report APL cases with submicroscopic 15; 17 recombinations leading to the formation of nonreciprocal PML/RARaor RARa/PMLfusion genes. Therefore, each of the two reciprocal translocation products may be independently formed and selected by the leukemic phenotype, implying that both are involved in tumorigenesis.