Analysis of cytogenetic characteristics in patients with myelodysplastic syndrome / 中国实验血液学杂志

This study was aimed to investigate the distribution of chromosomal aberrational karyotype in myelodysplastic syndrome (MDS) subgroups, the characterizations of numerical and structural aberration. The chromosome was prepared with simple culture of bone marrow, and the karyotype was analysed by G banding technique. The results showed tht 54 out of 127 patients (42.5%) had clonal chromosome aberrations, and the abnormal rates were different in subgroups: 30% (3/10) in MDS-RA, 35.9% (23/64) in MDS-RCMD, 22.2% (2/9) in MDS-RAS, 45% (9/20) in MDS-RAEB-I, 66.7% (14/21) in MDS-RAEB-II, 100% (3/3) in 5q-syndrome, respectively. Among 54 abnormal chromosome patients, 21 patients showed numerical aberration, 14 patients showed structural aberration, and the other 19 patients showed both numerical and structural aberration. The order of frequent aberrations was as follows complex karyotype (11.02%, 14/127), single +8 (10.24%, 13/127), -7/7q- (3.9%, 5/127), 1q+ (3.15%, 4/127), -X/-Y (3.15%, 4/127), 20q- (2.36%, 3/127), 5q- (2.36%, 3/127). The frequency of complex karyotype in MDS-RAEB (including RAEB-I and RAEB-II) was higher than that in non MDS-RAEB (including RA, RCMD, RAS, 5q-syndrome) (P < 0.05), and the frequency of balanced translocation was lower than that in non-balanced translocation (P < 0.05), and both of the two balanced translocation patients were found in MDS-RAEB. It is concluded that MDS is highly heterogeneous clonal disorder, a great majority of cytogenetic changes can be detected and most of which are recurrent aberrations, balanced translocations are rare, and only found in MDS-RAEB. The frequency of complex karyotype in MDS-RAEB is higher, and the patients with dup (1) (q21q32) recurrent abnormality is common in this study.

Analysis of ITD characteristics in acute myeloid leukemia patients with FLT3-ITD positive / 中国实验血液学杂志

The aim of this study was to analyze the FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) allelic ratios (AR), number of ITD, ITD length and positions of ITD insertions in de novo acute myeloid leukemia (AML) patients with FLT3-ITD positive, and the relationship between mutant level and therapeutic efficacy. Genomic DNA was amplified by PCR, capillary electrophoresis was used to detect the ITD characteristics in 31 de novo AML patients, and DNA sequences analysis of FLT3-ITD(+) were performed in 13 patients. The results showed that the ratios of mutant to wild type FLT3 allele ranged from 0.01 to 2.8; 28 patients (90.32%) had a single ITD, the remaining 3 patients had more than one ITD; the ITD length ranged from 3 to 144 bp in all FLT3-ITD(+) patients. 13 sequence-analyzed patients, 4 patients were of pure duplications, and 2 patients had foreign bases inserted, and the other 7 patients were partial duplications. The ITD occurred in the regions from p.E573 to p.P606 of the FLT3 protein, with the majority clustered in a stretch between p.F590 and p.R595. The complete remission (CR) rate in AR < 0.5 patients (43.75%) were more prevalent as compared with AR ≥ 0.5 patients (16.67%) (p > 0.05). It is concluded that the ITD length and AR are vary widely. Some of the insertions are foreign bases, and all of the 13 sequences-analyzed ITD were concentrated on the juxtamembrane domain. The CR rate in patients of AR < 0.5 had no statistical significance compared with patients of AR ≥ 0.5.

FMS-like tyrosine kinase 3 gene mutation in acute myeloid leukemia detected by denaturing PAGE and its clinical significance / 中国实验血液学杂志

The aim of this study was to analyze the frequency of flt3 length mutation (flt3-LM) in de novo acute myeloid leukemia patients and the relationship between flt3-LM and chromosome alterations, FAB subgroups, as well as efficiency of therapy. Genomic DNA was amplified by PCR; 2% agarose gel or 8% denaturing PAGE were used to detect the length mutation of flt3 gene in 99 de novo acute myeloid leukemia patients; karyotyping in 72 AML patients was performed by G banding technique. The results showed that the flt3-LM was detected in 20.2% (20/99) patients by agarose gel electrophoresis, and in 29.9% (29/99) by denaturing PAGE. The flt3-LM was not detected in M(0) (only one patient was available), but flt3-LM occurrence in AML subtypes was as follow: in M(2) (9/30), M(3) (6/27), M(4) (4/14), M(5) (7/19), M(6) (3/8) respectively. flt3-LM in patients with normal karyotypes (39.13%) was more prevalent as compared with patients of abnormal karyotype (24.49%), but there was no statistical difference (p > 0.05). The complete remission (CR) rate in flt3-LM positive patients (36.36%) was lower than that in flt3-LM negative patients (62.75%) in the 73 patients (p < 0.05) whose karyotypic detection was performed. The distributions of flt3-LM were observed in 8 out of 40 CR patients, 8 out of 21 PR patients, and 6 out of 12 NR patients. It is concluded that the denaturing PAGE is more sensitive and reliable to detect the flt3-LM. The flt3 mutation represents a common genetic abnormality in AML patients, and the flt3-LM is associated with lower CR rate.