ARMS-PCR combined with capillary electrophoresis can be a sensitive and quantitative method for detection of MYD88-L265P mutation in lymphoma / 中国实验血液学杂志

OBJECTIVE@#To investigate the feasibility of sensitive and quantitative detection of MYD88 gene L265P mutation in lymphoma patients by using ARMS-PCR combined with capillary electrophoresis.@*METHODS@#ARMS-PCR amplified MYD88 gene was analyzed by capillary electrophoresis in ABI 3730 sequencer; Exon 5 of the same gene was sequenced bi-directionally as reported.@*RESULTS@#The sensitivity of detection L265P mutations by the ARMS-PCR combined with capillary electrophoresis and direct sequencing was 0.2% and 5%, respectively, according to the detection of the gradient-diluted plasmid standards. The detection rate of 184 patients was 13.59% and 8.28%, respectively (p<0.001). Moreover, the former method can successfully detect the mutation ratio(R=0.979), and the repeatabilities (CV=2.86%, 1.94%, 5.49%) are acceptable.@*CONCLUSION@#ARMS-PCR combined with capillary electrophoresis can quantitatively detect the MYD88 gene L265P mutation, and the detection sensitivity is significantly higher than sanger sequencing. As a supplement to the latter, it can effectively lead to the earlier diagnose and monitoring of minimal residual disease.

Frequently ABL kinase domain G:C→A:T mutation and uracil DNA glycosylase abnormal expression in TKI-resistant acute lymphoblastic leukemia of Chinese population / 中国实验血液学杂志

Most Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(+) ALL) patients often show rapid recurrence and development of ABL kinase domain (KD) mutation after tyrosine kinase inhibitor (TKI) treatment. To further investigate the mechanism of Ph(+) ALL fast relapse after TKI treatment, ABL KD mutation in 35 Chinese Ph(+) ALL with TKI resistance was detected by direct sequencing. The results showed that 77.1% (27/35) Ph(+) ALL patients with TKI resistance had ABL KD mutation and 55.6% (15/27) Ph(+) ALL patients with ABL KD mutation had T315I. Interestingly, 77.8% (21/27) Ph(+)ALL showed ABL mutation G: C→A:T, including T315I, E255K and E459K. Furthermore, all the Ph(+) ALL patients with two or more ABL KD mutations collaborated with complex chromosome abnormality and all the TKI-resistant Ph(+) ALL patients, whose karyotype progressed from simple t (9;22) into complex, developed ABL KD mutation. Moreover, the expression level of uracil-DNA glycosylase UNG2, which inhibits G:C→A:T transition in genomic DNA, decreased in Ph(+) ALL with TKI-resistance compared to that in newly diagnosis Ph(+) ALL. It is concluded that there is a high frequent ABL KD G:C→A:T mutation and a high genomic instability in Chinese TKI-resistant Ph(+) ALL. In addition, the decreased UNG2 expression in TKI-resistant Ph(+) ALL probably contributes to their high rate of ABL KD G:C→A:T mutation.

The different characteristics of ABL kinase domain mutation in the Chinese Han nationality imatinib resistant Philadelphia chromosome-positive acute lymphoblastic leukemia and chronic myeloid leukemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To identify the distribution and differentiation of ABL kinase domain mutation in the Chinese Han nationality imatinib resistant chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(+)ALL).</p><p><b>METHODS</b>Bone marrow or peripheral blood samples of 112 imatinib resistant CML patients and 21 Ph(+)ALL patients were obtained from the first affiliated hospital of Soochow university according to local law. Total RNA was extracted from the mononuclear cells using a TRIzol reagent. ABL kinase domain (KD) mutation was detected by direct sequencing.</p><p><b>RESULTS</b>Of the 112 imatinib resistant CML patients, 54.46%(61 cases) had ABL KD mutation. Twenty-three mutants were identified in 20 amino acid sites and 23.21% (26 cases) ABL KD mutations were in P-loop region. ABL KD mutations were also detected in 71.43% (15 cases) imatinib resistant Ph(+)ALL patients, with 10 mutations in 8 amino acid sites. The most frequent mutation was T315I (28.57%), followed by E255K/V (19.05%) and Y253F/H (14.29%). The frequency of T315I was much higher in imatinib resistant Ph(+) ALL than that in imatinib resistant CML (P = 0.001). Ph(+)ALL with additional chromosomal aberrations also had a higher rate of ABL KD mutation than that of CML (P = 0.010). Ph(+)ALL gained ABL KD mutation faster than CML (P < 0.010).</p><p><b>CONCLUSION</b>Chinese imatinib resistant CML and Ph(+)ALL patients had different characteristics in ABL KD mutation. The rate of ABL KD mutation in Ph(+)ALL with additional chromosomal aberrations was much higher than that of CML with additional chromosomal aberrations.</p>

Clinical and laboratorial analysis for 15 adult cases of mixed phenotypic acute leukemia with Ph chromosome and/or positive BCR-ABL / 中国实验血液学杂志

The purpose of this study was to summary the clinical and laboratorial features in 15 adult cases of mixed phenotypic acute leukemia with Ph chromosome and/or BCR-ABL fusion gene positive (Ph(+)MPAL), 15 adult patients with Ph(+)MPAL were defined by WHO-2008 classification. The clinical characteristics, results of morphology, immunology, cytogenetics and molecular genetic detections and results of follow-up in 15 adult patients with Ph(+)MPAL were analyzed retrospectively. The results showed that 15 patients among 87 cases of MPAL demonstrated Ph(+)MPAL (17.2%; 15/87) (7 males and 8 females), their median age was 51 (range 16-81) year old and median WBC count at diagnosis was 69 (12.7-921)×10(9)/L. Based on FAB criteria, these patients showed different morphologic types, including AML (13.3%; 2/15), ALL (40.0%; 6/15), HAL (46.7%; 7/15). Immunologic analysis indicated that 15 cases of Ph(-)MPAL were all classified as B-lymphoid +myeloid mixed immunophenotype. Except one patient, all expressed CD34 antigen on the surface of leukemia cells with 64.3% strong positive, only Ph (53.3%; 8/15), Ph with additional chromosomal abnormalities (33.3%; 5/15) and normal karyotype (13.3%; 2/15) were cytogenetically identified. BCR-ABL fusion gene transcript positive were detected by multiplex reverse transcription PCR in all cases, with e1a2 subtype (p190) (40.0%; 6/15) and b2a2 or b3a2 (p210) subtype (60.0%; 9/15). Four out of 7 (57.1%) patients were found to have IKZF1 gene deletion, without other common gene mutations. Seven out of 10 cases (70.0%) achieved complete remission (CR) after one cycle of induction chemotherapy. In the induction stage, CR rate seemed higher when tyrosine kinase inhibitors (TKI) were added to chemotherapy (83.3%:50.0%; P = 0.206). Overall survival (OS) in 4 patients received allogeneic hematopoietic stem cell transplantation (allo-HSCT) was longer than that in 4 patients received chemotherapy alone (P = 0.004). It is concluded that Ph(+)MPAL mainly is expressed as B+My phenotype. The majority of patients is older and has CD34 overexpression. In the aspect of molecular genetics, the Ph(+)MPAL is similar to other acute leukemia with Ph chromosome. Ph(+)MPAL is a subtype of acute leukemia with poor prognosis. WBC count at diagnosis is an independent prognostic factor. The combination of TKI and allo-HSCT can improve their long-term survival, which needs to be confirmed through carrying out a prospective and multicenter clinical trial for newly diagnosed Ph(+)MPAL.

C-kit, NPM1 and FLT3 gene mutation patterns and their prognostic significance in 656 Chinese patients with acute myeloid leukemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To evaluate the prevalence and distribution of C-kit, NPM1 and FLT3 gene mutations in patients with acute myeloid leukemia (AML), and to analyze the relationship between the gene mutations and their prognosis.</p><p><b>METHODS</b>Mutations in exon 8 and 17 of C-kit gene, exon 12 of NPM1 gene, exon 20 of FLT3-TKD gene, and exon 14/15 of FLT3-ITD gene were detected by direct sequencing. Clinical data was collected and followed up if the patient had accepted treatment in our hospital.</p><p><b>RESULTS</b>Among the 656 AML patients, mutations in C-kit exon 8 were found in 6 patients (0.9%), C-kit exon 17 in 33 (5.0%), NPM1 in 169 (25.8%), FLT3-TKD in 46 (7.1%), and FLT3-ITD in 178 (27.1%). Six subtypes of mutations were detected in C-kit exon 8, 8 in C-kit exon 17, 11 in FLT3-TKD, 15 in NPM1, of which 5 were not reported before. C-kit exon 17 mutations were more frequently detected in patients with t(8;21) and exon 8 in patients with inv(16) cytogenetic abnormality. No other gene mutations except FLT3 were detected in M(3) patients. NPM1 and ITD mutations were often detected in individuals with normal cytogenetics or M(5) and M(1) of FAB classification, and accompanied with high white blood cell counts in peripheral blood, high blast counts in bone marrow and low CD34 expression. The older the patients were when diagnosed, the more gene mutations and the higher white blood cell count were detected. More mutations were found in individuals with normal karyotype than that with other karyotypes. It appeared that FLT3-ITD was significantly associated with shorter overall survival (OS) (P = 0.004), NPM1 was not significantly associated with OS, but NPM1(+)/ITD(-) patients had the longest OS.</p><p><b>CONCLUSIONS</b>Our results showed that the mutation types and amounts had particular distribution in MICM subtypes, and were associated with white blood cell counts in peripheral blood, blast counts in bone marrow and prognosis. Especially for patients with normal karyotype, the genetic mutations could be new molecule marker.</p>

The incidence of TET2 gene mutation and its clinical significance in acute myeloid leukemia patients / 中华血液学杂志

<p><b>OBJECTIVE</b>To evaluate the prevalence of TET2 gene mutation in acute myeloid leukemia (AML) patients, and analyze their clinical characteristics and prognosis.</p><p><b>METHODS</b>Polymerase chain reaction (PCR) and direct sequencing were used to sequence exon 3 to 11 of TET2 gene.</p><p><b>RESULTS</b>Among 96 AML patients, TET2 gene mutation was detected in 13 (13.54%) patients (95%CI 6.70% - 20.38%). The median age was 54 years in mutated group and 41 years in unmutated group (P = 0.010). Mutated and unmutated patients did not significantly differ in gender, white blood cells (WBC) count at diagnosis, platelet count, PB and BM blast percentage and chromosome karyotype, excepting for hemoglobin level 84 (70 - 108) g/L in mutated group versus 70 (55 - 87) g/L in unmutated group (P = 0.032). TET2 gene mutation had no significant correlation with C-KIT, FLT3, JAK2V617F mutations, but did with NPM1 mutation. TET2 mutated patients had lower CR1 rate and 2-year overall survival than unmutated in non-M(3) patients (P < 0.05).</p><p><b>CONCLUSIONS</b>TET2 gene mutation is more prevalent in older AML patients and has a certain correlation with clinical characteristics and outcome. It may be a molecular marker for poor prognosis in AML.</p>

Analysis of tyrosine kinases gene mutations in core binding factor related acute myeloid leukemia and its clinical significance / 中华血液学杂志

<p><b>OBJECTIVE</b>To assess the prevalence of several tyrosine kinases (TKs) gene mutations including c-Kit, FLT3 and JAK2 V617F in core binding factor related acute myeloid leukemia (CBF-AML), and analyze their impact on clinical characteristics and prognosis.</p><p><b>METHODS</b>Mutations of c-Kit, FLT3-ITD and FLT3-TKD were detected by genomic DNA PCR and sequencing, and JAK2 V617F mutation screening by allele-specific PCR in 58 newly diagnosed CBF-AML patients [28 AML with inv(16) and 30 with t(8;21)], and analyze the patients clinical characteristics and prognoses.</p><p><b>RESULTS</b>c-Kit aberrations were detected in 32.8% cases, including 6 cases mutated in exon 8 (mutKIT8) and 13 mutated in exon 17 (mutKIT17). MutKIT8 was more prominent in inv(16) than in t(8;21) patients (21.4% vs 0, P = 0.009). Only 2 cases had FLT3-ITD and 7 (12.1%) FLT3-TKD mutations. The result of JAK2 V617F mutation screenings in these CBF-AML patients was negative. The frequency of receptor tyrosine kinases(RTK) mutations was 46.6% and only one case had two kinds of missense mutations (mutKIT8 & TKD(+)). Median age of onset was higher for mutKIT17 than for wide-type c-Kit (wtKIT) patients (55 vs 31, P = 0.003). c-Kit mutations were significantly associated with decreased overall survival (OS) and continuous complete remission (CCR) rates (P = 0.053, and 0.048 respectively), and so did more for exon17 mutated patients reduced (P = 0.005, and 0.013 respectively). FLT3-TKD mutation showed no effects on prognosis of CBF-AML patients.</p><p><b>CONCLUSIONS</b>RTK mutations are common in patients with CBF-AML. c-Kit mutations frequently and JAK2V617F mutation rarely appear in CBF-AML. c-Kit mutations, especially mutKIT17 confers higher relapse risk and poorer prognosis.</p>