Most patients with APL express del(17q)-derived RAR alpha-PML transcripts as well as the putative leukemogenic PML-RAR alpha associated with add(15q).     ///    Minimal residual disease detection in acute promyelocytic leukemia by reverse-transcriptase PCR: evaluation of PML-RAR alpha and RAR alpha-PML assessment in patients who ultimately relapse..     ///    The RAR alpha-PML assay changed the PCR status of two patients in morphological remission.     ///    "Although parallel assessment of PML-RAR alpha and RAR alpha-PML can enhance minimal residual disease detection in APL, this study demonstrates that treatment strategies involving determination of PCR status post-consolidation, even using RAR alpha-PML in addition to the more conventional PML-RAR alpha assay will fail to identify all patients at risk of relapse. "    ///    "We have found that a nested RT-PCR for RAR alpha-PML affords greater sensitivity than that for PML-RAR alpha, particularly in patients with the commonest breakpoint pattern. "