Abstract:

Objective To investigate the roles of conventional cytogenetics（CC） and fluorescence in situ hybridization（FISH） in the diagnosis of mixed linage leukemia（MLL） gene abnormality and chromosome 11q23 abnormality in childhood acute leukemia（AL）. Methods Totally，404 AL children were enrolled from the Children's Hospital of Shanghai from June 2016 to June 2021. The cytogenetic analysis was performed by CC and FISH. The determination rates for MLL gene abnormality were compared between the 2 methods. Results There were 404 AL children. The 57 cases of abnormal MLL gene（14.1%） were determined by FISH，which included 40 cases of acute lymphoblastic leukemia（ALL），and there were 23 cases of abnormal MLL gene signal number and 17 cases of MLL rearrangement. There were 17 cases of acute myeloid leukemia（AML），and 2 cases had abnormal MLL gene signal number and 15 cases of MLL rearrangement. Chromosomal abnormalities of MLL gene were determined in 27 cases（6.7%），there were 15 cases of ALL，and MLL rearrangement partner gene was identified in 13 cases. There were 12 cases of AML，and MLL rearrangement partner gene was identified in 11 cases. Conclusions The abnormal rate of MLL gene determined by FISH is higher than that by CC. CC can intuitively present the abnormal types of MLL rearrangement and identify its partner genes. The 2 determination methods play roles in the diagnosis of MLL gene abnormality in AL.

Key words: Mixed linage leukemia gene, Cytogenetics, Fluorescence in situ hybridization, Children