Objective: To evaluate the significance of PML-RAR alpha transcripts in patients with acute promyelocytic leukemia (APL) during remission period and to follow up the patients through monitoring aberrant gene expression.
Patients and methods: This study included 17 patients with APL (5 females and 12 males). Another 19 APL patients during relapse served as control. RNA extraction was obtained through the single-step method. By means of reverse transcriptase polymerase chain reaction (PCR), the PML-RAR alpha was detected in the sample mRNA.
Results: Nine out of 10 patients with complete remission (CR) duration shorter than 3 years were positive. Four cases became negative and three remained positive among 7 cases in a long remission of over 3 years. The difference of the positive rate of PML-RAR alpha transcripts between the 2 groups was significant (P < 0.05). Four among 12 positive cases relapsed. No evidence of relapse was present in the 5 negative patients after 9.6 +/- 3.9-month follow-up. Further treatment was therefore given to the 4 positive patients whose treatment was already ceased at that time. By this management they were all in CR during the following 10-month observation.
Conclusions: RT-PCR detection for PML-RAR alpha transcripts was useful in monitoring MRD and guiding further treatment to obtain a long remission. Persistently positive transcripts were closely associated with the relapse.