RARα/MYL FUSION mRNA IS A SPECIFIC MARKERFOR DIAGNOSIS AND MONITORING OF ACUTE PROMYELOCYTIC LEUKEMIA
Le Xiao feng ;Chen Shanshan ;Fu Jiayu;et al(Institute of Hematology ,Beijing Medical University Beijing,100034)
he RARα/MYL fusion transcripts were determinedin bone marrow samples from2 0 cases of de novo acutepromyelocytic leukemia(APL)by reverse transcriptase-polymerase chain reaction(RT-PCR)technique. Fourprimers(R5 ,R6;D3;D4)were u;ed in this study.Thetest was able to detect the amplified R ARα/MYL fusiontranscripts in the presence of 0.1lng total RNA,whichrepresented cell dilution in 10￣(-4)～10￣(-5).The specificityof amplified products could be further identified by Kpn Icleavage test. Ninety percent(1 8/20)cases expressedtype B form (290 bp fragment) and the other two casesbelonged to type A form(311 bp fragment).Seven ofthe 20 cases were able to be followed up after treatrnent.The fusion mRNA was still detected in two patients whohad been in cornplete remission(CR) for 4 and 16 weeksrespectively. One patient showed continuouslv RT-PCRpo;itive during CR and relap:ed morphologically fourweeks later. Other 4 patietns in CR were RT-PCR neg-ative during 9～29 weeks follow-up.Two caseswith acute myeloid leukemid, were classifiedasFAB-M_3before retinoid acid treatment,but their RT-PCR results were negative. Both of thern failed in thetreatment,and their karyotype showed typical t ( 8; 21)and normal respectively. We concluded that detection ofthe RARα/MYL fusion mRNA was compatible with MYL/RARα fusion mRNA,it was also a senshive andspecific marker for diagnosis and monitoring of minimalresidual disease in APL.