ACUTE PROMYELOCYTIC LEUKEMIA CASES WITH NONRECIPROCAL PML RARA OR RARA/PML FUSION GENES/

Tumor-associated chromosome translocations usually lead to the formati on of two reciprocal fusion genes: one thought to be involved in the t ransformation process, the other the mechanical consequence of the tra nslocation event. In the case of acute promyelocytic leukemia (APL) bl asts, the 15;17 chromosome translocation generates the putatively tran sforming PML/RARa fusion gene and its reciprocal RARa/PML. We report A PL cases with submicroscopic 15;17 recombinations leading to the forma tion of nonreciprocal PML/RARa or RARa/PML fusion genes. Therefore, ea ch of the two reciprocal translocation products may be independently f ormed and selected by the leukemic phenotype, implying that both are i nvolved in tumorigenesis. (C) 1995 by The American Society of Hematolo gy.