Cytogenetic Analysis And Its Clinical Significance In Leukemia

Objective To investigate the chromosome abnormalities in leukemia, which to evaluate the value of ctyogenetic analysis can serve as an effective index for clinical diagnosis , reatment estimation of prognosis in leukemia . The results of FISH were compared with those of conventional cytogenetics (CC) assay , to observe sensitivity, rapid effect and Specificity of FISH technology in the detection of common chromsome abnormalities in malignant hematopathy.Methods 1. Patient samples: Bone marrow or blood cells were obtained from 107 patients with leukemia , 20 patients with MDS and 20 controls for chromosome and frozen cell purpose. 2. Established method of common chromosome with leukemia The chromose were prepared with direct method,brief culture of cells .3. The karyotype was detected by conventional cytogenetic R-banding (CCR) and G-banding (CCG) . 4. Criterion of abnormal karyotype:Twenty cells for normal slide sample. The final result were named by the International System for Human Cytogenetic Normenclature , Mitelman F(ed); S. arger,Basel,1995. 5. Criterion of positive FISH results: By the FISH probe kit (bcr/abl probe)to study the bcr/abl fusion gene in chronic myeloid leukemia (CML ) cases with Philadelphia chromosome(Ph) negative , and variant Ph translocations and other chromosome anomalies, cases of MDS patients, whose karyotypes were unknown by the FISH examiner beforehand , were analyzed with a panel FISH using YAC248F5 (5q31) ,YAC938G5 (7q32),CEP8 and YAC912C3 (20ql2) probes to detect the frequently occurring chromosome abnormalities(-5/5q,-/7q-,+8,20q-)in MDS. Then the results were compared to those of conventional cytogenetics (CC). To observe the bcr/abl hybridized gene of interphase and metaphase nucleus cells of bone marrow with fluorescence microscope .Results 1. Abnormal karyotype result in each group 1.1 positive result There were total abnormal 77 cases in the group, there were 28 kings abnormal karyotype,21 kings were specific abnormal karyotype,the most sum abnormal are +8 +7 . -7 abnormal chromsome, which includes 33 of AML, 9 of ALL ,23 of CML, 2 of CLL respectively, 10 of MDS. All the results in control group are normal. 1.2 positive rate: The total positive rate was 61% . 57% for AML,which includes 67% AML-M1,58% for AML-M2, 56% for AML-M3,44% for AML-M4, 64% for AML-M5 respectively; 53% for ALL ,which includes 66% for LI, 58% for L2,0% for L3 respectively; 85% for CML group, 40% forCLL, and 50% for MDS group respectively, there were the most abnormal chromosomes for t(15;17),t ( 9;22 ) ,t(8;21),5q-,21q-,9q-,7q- and Ilq23, t(8;21), t(15;17), t/del(llq23)and t(9;22) are discoved in 33% of M2 42% of M3, 25% of M5 and 85%of CM, and 85% of t(8;21), 100% of t(15;17) 75% of t/del(llq23) were discoved in M2. M3 M5 is of patients. 1.3 To contrast the positive rate of abnormal chromosomes on the initial to the remission : There were total abnormal 50 cases in the initial, the total positive rate 68% (58/85) ;and 23 cases in the remission, the positive rate 30% (7/23) , the results showed them was the significant difference. 1.4 Rare karyotype results: we reported 3 cases new abnormal karyotype the first time in the world: 45,XY,t(8;21)(q22;q22),ider(21)(ql0)t(8;21)(q22;q22),der(16;17)(pl0;ql0);46,XX, t(ll;12)(pl5?;pl3?);46,XY,t(5;12)(q23;ql3). 1.5 chromosome abnormalities were specifically associated with leukemia prognosis: the 86 cases of regular therapeusis have been observed and follow-up , 29 (81%) cases were remission and 6(21%)cases were recur in 36 case of the normal karyotype . 34(68%) cases were remission and 13(38 %)cases were relapse in 50 case of the abnormal karyotype . the results showed them was the significant difference.(P<0.05) . the complete remission rates of leukemia were significantly higher and relapse rates were lower in patients with the normal karyotype than patients with the abnormal karyotype . patients with the normal karyotype, ultratwiceploid ,t(15;17)and part of t(8;21) showed the best therapeutic effect , while patients with the abnormal karyotype , -7/7q\ t(9;22)? t(4;ll)and complex translocation manifested the poor the rapeutic effect, them often were died and relapsed 2. Criterion of positive FISH results: 2.1 27 cases of interphase fluorescence in situ hybridization(FISH) which have been one green and one yellow signals in 25 cases( 93%),it means the rearrangement of bcr/abl gene expression, then with ctyogenetic analysis the positive rate of abnormal chromosomes was only 85% ,The difference in the percentage of positive cells detected by the two methods was statistically significant (P<0.05) , Interphase FISH was more simple , rapid and sensitive than CC for the detection of bcr/abl gene expression in CML; 2. FISH using YAC248F5 (5q31), YAC938G5 (7q32) ,CEP8 and YAC 912C3 (20ql2) probes to detect the frequently occurring chromosome abnormalities(-5/5q",-7/7q', +8 ,20q") in MDS. Among 20 cases , 14 cases were found to carry common chromosome abnormalities by FISH,however , on CC examination , only ten cases were found to have common chromosomal abnormalities, To explore FISH was a useful tool of molecular cytogenetics in the detection of common chromosome abnormalities in MDS.