Abstract： [Objective] To investigate combined application of multiplex reverse transcription-polymerase chain reaction (mRT-PCR) and karyotype analysis detect of clonal chromosomal aberrations in acute lymphoblasfic leukemia (ALL),and explore the expression of common fusion genes.Methods 189 ALL patients were examined by multiplex RT-PCR and R or G banding techniques.[Results]10 fusion genes were detected in 69 out of 189 ALL patients(36.5％),including E2A/PBX1,TEL/AML1,BCR/ABL,MLL/AF4,MLL/AF6、MLL/AF9,MLL/AF10,MLL/ELL,SIL/TAL1,TLS/ERG.R or G banding techniques could find chromosome structural and numeracy abnormalities in 86 out of 152 patients (56.6％) available for analysis.Combination of mRT-PCR and R or G banding could raise the rate of detecting clonal chromosomal abnormalities to 69.3％.Fusion genes were detected in 33 out of 90 (36.7％) patients with adult ALL and 36out of 99 (36.4 ％) patients with children ALL,there were 22 patients with positive BCR/ABL but no TEL/AML1 in adult ALL group,while there were 24 patients with positive TEL/AML.1 and 2 with positive BCR/ABL in children ALL group.There was significant statistical difference for the expression of RCR/ABL and TEL/AML1 between adult ALL and children ALL (P＜0.01),but no difference for MLL related fusion gene,E2A/PBX1,SIL/TAL1 and TLS/ERG(P＞0.05).BCR/ABL and TEL/AML1 fusion gene could be detected in 66 ALL patients with normal karyotype (36.3％).[Conclusion]There were different biological characteristics between adults and children with ALL.mRT-PCR technique can quickly screen chromosome structural aberrations in patients with newly diagnosed leukemia.It is useful in detection of fusion genes in ALL with normal karyotypes and it would refine the karyotype analysis and provide imrootramt prognosis-relevant information.