Research On The 3D Organization Of Chromosomes For Leukemia By 3D-FISH

Chromosomes are the basic genetic materials in nuclei.Generally,interphase chromosomes are steadily positioned in nuclei.Spatial organization of chromosomes in nuclei is related with gene expression and epigenetic regulation.Abnormalities of chromosomal organization are primary causes of many huge diseases such as cancer.Nearly all patients with cancer are companied with abnormal organization of chromosomes,including deletion,duplication,break,translocation,inversion,etc.Three-dimensional fluorescence in situ hybridization?3D-FISH?,which is characterized as in situ and almost non-destructively labeling tissues and cells in three dimensions,combined with confocal laser scanning microscope?CLSM?is the recent most important technique to study chromosomal organization.We applied 3D-FISH directly to clinical research of acute myeloid leukemia?AML?M₂ patients with t?8;21??q22;q22?and M₃ patients with t?15;17??q22;q12-q21?.We tracked patients consecutively to study spatial organization of interphase chromosomes in mononuclear cells isolated from bone marrow?BM?of the patients.In addition,we compared and analyzed spatial organization of chromosomes between BM and periphery blood?PB?.Firstly,we proposed a new analysis method to study spatial organization of interphase chromosomes in nuclei for mononuclear cells of BM and PB using 3D-FISH.Based on the spatial organization of chromosomes,we classified cells into normal,proximal,and malignant cells.Both donors with normal karyotype and AML patients were included in the research.We studied the change of spatial organization of chromosomes for BM extracted from AML-M₂ and M₃ patients who were consecutively tracked especially before relapse.We found the early warning of relapse for chromosomal organization detected by 3D-FISH,and speculated that a patient might deteriorate if there were more than 20%malignant cells in his BM.Secondly,we analyzed spatial position of interphase chromosomes for M₂ and M₃patients,includingco-localizedandtranslocation-associatedheterogenous chromosomes.In addition,we studied the change of spatial position of interphase chromosomes for consecutively tracked patients especially before relapse,and speculated that centralization of chromosomes in interphase nuclei might be one of the causes of translocation occurance and disease relapse.Finally,we compared spatial organization of interphase chromosomes in nuclei between BM and PB extracted at the same time from several patients.We also studied the influence of treatment on spatial position of chromosomes for BM and PB.We concluded that PB should be used as a supplementary alternative of BM for clinical diagnosis especially during the treatment.We used 3D-FISH directly to the comprehensive research of clinical AML patients,and provided a potential method for early detection of relapse for AML patients.In addition,results in this work might support the futher research on mechanism of AML relapse.