Cytogenetic Analysis Of Acute Myeloid Leukemia (M4/M5) And The Detection Of The Disorder Of MLL Gene Expression By Fluorescence In Situ Hybridization

Objective To investigate the disorder of mixed lineage leukemia gene expression by ctyogenetic analysis and fluorescence in situ hybridization in patient with acute myeloid leukemia(M4/M5).Methods (1) Patient samples: Bone marrow or blood cells were obtained from 113 patients with acute leukemia and 20 controls for chromosome and frozen cell purpose. Among these 113 patients, there were 70 cases of acute myeloid leukemia (AML), which includes 3 of AML-M1, 16 of AML-M2, 20 of AML-M3, 14 of AML-M4, 17 of AML-M5 according to FAB classification. The others were 28 cases of acute lymphoblastic leukemia, including 20 new or unremissioned cases and 8 completed remission cases after therapy. And there are also 10 chronic myeloid leukemia and chronic lymphoblastic leukemia patients. The blast percentages of all new cases were not less than 60%. The control cases were patients without malignant disease of hematopoietic system and result of their bone marrow inspection were not found abnormality. The specimen were cultured in vitro in 24 hours for making chromosome samples in order to detect the abnormal karyotype, especial the changes happen in Ilq23. (2) Criterion of abnormal karyotype: Ten cells for abnormal slide sample and twenty cells for normal slide sample. The final result were named by the International System for Human Cytogenetic Normenclature, Mitelman F (ed); S. Karger, Basel, 1995. (3) Criterion of positive FISH results: The FISH probe which marked with red and green fluoresceins come from Vysis Spectra Vysion FISH probe kit made in Applied Imaging Company. One red, one green and one yellow signals were observed in the interphase image means the rearrangement of MLL gene expression. Then all the data were dealed with statistics technique of rank sum, analysisi of variance, and Chi-squared test.Results (1)Abnormal karyotype result in each group(1)positive result: There are total abnormal 24 cases in AML group, which includes 2 of AML-M1, 3 of AML-M2, 5 of AML-M3, 7 of AML-M4, 7 of AML-M5 respectively. And total 5 abnormal cases were detected in ALL group, which includes 2 of LI, 3 of L2, 0 of L3respectively. And total 9 abnormal cases were detected in CML group, 2 in CLL group. All the results in control group are normal (2)positive rate: 66% for AML-M1, 18.75% for AML-M2, 25% for AML-M3, 50% for AML-M4, 41.18% for AML-M5 respectively; 22.22% for LI, 20% for L2, 0% for L3 respectively; 34.29% for AML group, 17.86% for ALL group, 90% for CML group and 40% for CLL group respectively. The total positive rate is 35.40%. (3)Rare karyotype result for M4/M5 group: we reported 2 cases for the rearrangement of NUP98 gene in AML-M4 group, 1 case t(16;21)(p11; q22) in AML-M5 group,4 cases for the rearrangement of MLL gene expression which were verified by FISH in AML-M5 group AML-M2 group, 2 cases +4 and 1 case +8 in AML-M5 group and 1 case 9q" in AML-M4 group. We also reported one new abnormal karyotype(M5a: 46,XY,t(5;12)(q23;q13)) the first time in the world.Conclusions The study shows that the cytogenetic analysis for the leukemia patients was important and essential. The result of the karyotype will help us to estimate the rank of the risk for the patient respectively and thus it will help us to make the therapy plan individually. The FISH technique is a sensitive method in detecting the rearrangement of MLL gene and it is a significant molecular cytogenetic method in karyotype examination.