 Six patients with acute promyelocytic leukaemia (APL) and t(15;17) were investigated by cytogenetics and by reverse transcriptase polymerase chain reaction (RT-PCR) for the fusion transcript PML-RARA.     ///    Thereafter the PML-RARA transcript was not seen in 20/21 first remission samples in five cases studied.     ///    "Despite serial negative RT-PCR results, PML-RARA reemerged at or prior to relapse following BMT in the remaining three cases. "