Long-term disease-free acute promyelocytic leukemia patients really can be cured at molecular level.

The characteristic t(15;17) translocation involving chromosomes 15 and 17 is specifically associated with both the common and the variant subtypes of acute promyelocytic leukemia (APL) (M3 according to FAB classification). At the molecular level, it fuses genes encoding PML on chromosome 15 and the nuclear retinoic acid receptor-alpha (RAR alpha) on chromosome 17. The subsequent expression of PML/RAR alpha fusion mRNA provides a potential molecular marker that can be detected in leukemic cells taken from patients with APL. Using PML and RARa sequence specific primers, reverse transcription-polymerase chain reaction (RT-PCR) assays have been developed for detection of PML/RAR alpha transcript in leukemic cells obtained from patients; these RT-PCR assays are more sensitive than conventional cytogenetic analysis.