RESUMEN
To study the incidence, the types of fusion genes and the clinical significance of rearrangements of mixed lineage leukemia (MLL) gene in acute leukemia (AL), the rearrangements of MLL gene of 60 patients with AL were detected by fluorescence in situ hybridization (FISH) and 6 types of common fusion genes resulting from the rearrangements of MLL gene were detected by nested RT-PCR. The results showed that 7 out of 60 AL patients were found the rearrangements of MLL gene, the incidence of which was 11.67%. 2 out of 7 patients were diagnosed as AML-M(5), 5 patients were diagnosed as B-ALL. The fusion genes of the 2 AML-M(5) patients who had the rearrangements of MLL gene were MLL/AF(9). Among 5 B-ALL patients, 2 patients were confirmed to express MLL/ENL, 1 patient was confirmed to express MLL/AF(4), the other 2 patients did not express the fusion genes. It is concluded that FISH is a fast, specific and sensitive method to detect the rearrangements of MLL gene in AL patients and nested RT-PCR is a convenient and feasible method to detect the types of fusion genes resulting from the rearrangements of MLL gene. The detection of MLL gene rearrangement is of great importance in predicting prognosis and guiding therapy in AL.