急性淋巴细胞白血病患者FLT3基因及FLT3/ITD基因突变的检测及临床意义

目的:研究急性淋巴细胞白血病(ALL)患者FLT3基因及其内部串联重复(ITD)突变情况。方法:采用多聚酶链反应(PCR)联合单链构象多态性(SSCP)方法检测76例不同免疫分型ALL患者FLT3基因及FLT3/ITD基因突变。结果:76例ALL患者经PCR扩增发现46例(60.5%)FLT3基因检测阳性,其中前前B细胞ALL、前B细胞ALL、成熟B细胞ALL及T细胞系ALL患者FLT3基因检测阳性率分别为88.2%(15/17),73.9%(17/23),40.0%(6/15)和23.5%(4/17);前前B细胞ALL和前B细胞患者ALL FLT3基因检测阳性率80.0%,显著高于成熟B细胞ALL(40.0%)(P<0.01);B细胞系ALL患者FLT3基因检测阳性率为69.1%,显著高于T细胞系ALL患者(23.5%)(P<0.01)。76例ALL患者中仅有2例(2.6%)出现FLT3/ITD基因突变,此2例均为伴有2种髓系抗原表达,免疫学检查诊断为急性混合细胞白血病患者,均伴有外周血高白细胞数、骨髓中高白血病细胞比例及预后较差。结论:B细胞系ALL和T细胞系ALL患者均可检测出FLT3基因,但B细胞系ALL患者FLT3基因检测阳性率显著高于T细胞系ALL;B细胞系ALL中细胞分化越成熟则FLT3基因检测率阳性越低。ALL患者一般不出现FLT3/ITD基因突变,FLT3/ITD基因突变检测可能有助于急性白血病基因分型及预后判断。     

FLT3突变与白血病预后的研究进展

FLT3又称FLK-2、STK-1,为Ⅲ型受体酪氨酸激酶成员之一,与其配体在正常造血及免疫系统的发育中起重要调节作用.FLT3在急性髓细胞白血病(AML)及急性B淋巴细胞白血病(B-ALL)中有过度表达,其突变是AML中最常见的基因异常.最近研究表明,FLT3过度表达与其突变均可作为预后不良因素,FLT3及其突变可能作为微小残留病灶(MRD)的标志.本文就FLT3及其突变在各型白血病中对预后的意义作一综述.     

FLT3突变急性髓系白血病的全程管理

约30%的新诊断急性髓系白血病(AML)患者携带FMS样受体酪氨酸激酶3(FLT3)基因突变,大多数FLT3突变是近膜结构域内的内部串联重复(ITD),也有少数是酪氨酸激酶结构域(TKD)内的点突变。FLT3抑制剂的应用改变了FLT3突变AML患者的治疗现状与预后。文章就FLT3突变AML的生物学特征,FLT3突变检测与诊断、FLT3抑制剂的应用及异基因造血干细胞移植中的作用等全程管理进行讨论。     

结直肠癌患者血癌胚抗原mRNA检测的临床意义

背景:结直肠癌预后不佳,进一步研究结直肠癌患者肿瘤标记物的表达及其与肿瘤临床病理特征的关系对指导临床治疗具有重要意义.目的:检测结直肠癌患者的外周血癌胚抗原(CEA)、CEA mRNA以及肿瘤回流静脉血CEAmRNA,探讨血CEA mRNA检测在结直肠癌诊治中的临床意义.方法:以酶联免疫吸附测定(ELISA)检测71例结直肠癌患者的外周血清CEA,同时以巢式逆转录聚合酶链反应(RT-PCR)检测其外周血(71例)和肠系膜上静脉血(35例)CEA mRNA.分析血CEA和CEA mRNA的表达与结直肠癌临床病理特征的关系.结果:结直肠癌患者的外周血CEA mRNA阳性率为69.0%,显著低于肠系膜上静脉血的82.9%(P<0.05),外周血CEA阳性率(45.1%)显著低于CEA mRNA阳性率(P<0.01).Dukes C期和D期结直肠癌患者的外周血CEA和CEA mRNA阳性率显著高于A期和B期患者(P<0.05).Dukes D期肝转移患者肠系膜上静脉血CEA mRNA阳性率为85.7%(6/7).结论:检测外周血CEA mRNA有助于结直肠癌患者的预后判断,肿瘤回流静脉血CEA mRNA的检测对结直肠癌肝转移的诊断具有重要意义.     

胃液中肿瘤相关抗原MG_7Ag的检测及临床意义

为探讨提高胃癌患者胃液中肿瘤相关抗原的检出率及早期胃癌检测的敏感性，应用以胃癌单克隆抗体的特异性和聚合酶链反应（ＰＣＲ）的高度敏感性相结合建立的免疫－ＰＣＲ检测胃液中肿瘤相关抗原ＭＧ７Ａｇ。结果胃癌３７例、慢性萎缩性胃炎８例、慢性浅表性胃炎４例及消化性溃疡８例，胃液中ＭＧ７Ａｇ阳性分别为３０例、２例、０例及１例，胃癌患者胃液中ＭＧ７Ａｇ的阳性检出率为８１．１％。结果提示该方法对诊断胃癌有较大的应用价值     

胃液中肿瘤相关抗原MG7Gg的检测及临床意义

为探讨提高胃癌患者胃液中肿瘤相关抗原的检出率及早期胃癌检测的敏感性，应用以胃癌单克隆抗体的特异性和聚合酶链反应（ＰＣＲ）的高度敏感性相结合建立的免疫－ＰＣＲ检测胃液中肿瘤相关抗原ＭＧ７Ａｇ。结果胃癌３７例、慢性萎缩性胃炎８例、慢性浅表性胃炎４例及消化性溃疡８例，胃液中ＭＧ７Ａｇ阳性分别为３０例、２例、０例及１例，胃癌患者胃液中ＭＧ７Ａｇ的阳性检出率为８１．１％。结果提示该方法对诊断胃癌有较大的应用     

肺癌K－ras基因突变的检测及临床应用

为探讨基因检测在肺癌中的应用价值，应用ＰＣＲ－ＲＦＬＰ法检测１０２例肺癌患者手术标本中Ｋ－ｒａｓ基因第１２密码子突变的状况。并将肺腺癌按临床病理特征分组进行对比分析。结果显示，肺癌中总突变率为２４％，腺癌中为４９％，鳞癌为１５％，而小细胞癌中无一例突变。吸烟是促发Ｋ－ｒａｓ基因突变的重要因素（Ｐ＜０．０５），肺腺癌突变组淋巴结转移早、部位远，其一年复发率达８５％，明显高于未突变组（Ｐ＜０．０１）。Ｋ－ｒａｓ基因突变的检测具有重要的临床意义和应用价值。     

改良PCR/SSCP和PCR直接测序在基因突变检测中的应用

改良ＰＣＲ／ＳＳＣＰ和ＰＣＲ直接测序在基因突变检测中的应用崔建涛吕有勇北京医科大学临床肿瘤学院北京市肿瘤防治研究所北京市１０００３４Ｓｕｂｊｅｃｔｈｅａｄｉｎｇｓｐｏｌｙｍｏｒｐｈｉｓｍ，ｓｉｎｇｌｅｓｔｒａｎｄｅｄｃｏｎｆｏｒｍａｔｉｏｎａｌ...     

肺癌K—ras基因突变的检测及临床应用

为探讨基因检测在肺癌中的应用价值，应用ＰＣＲ－ＲＦＬＰ法检测１０２例肺癌患者手术标本中Ｋ－ｒａｓ基因第１２密码子突变的状况。并将肺腺癌按临床病理特征分组进行对比分析。结果显示，肺癌中总突变率为２４％，腺癌中为４９％，鳞癌为１５％，而小细胞癌中无一例突变。吸烟是促发Ｋ－ｒａｓ基因突变的重要因素（Ｐ〈０．０５），肺腺癌突变组淋巴结转移早、部位远，其一年复发率达８５％，明显高于未突变组（Ｐ〈０．０１）。     

亚洲乙型肝炎病毒前C区突变检测的临床意义

１９８９年Ｂｒｕｎｅｔｔｏｅｔａｌ［１］和Ｃａｒｍａｎｅｔａｌ［２］先后报道抗Ｈｂｅ阳性的慢性肝炎患者中,发现了ＨＢＶ前Ｃ区突变株,即在前Ｃ区１８９６点ＴＧＧ转变为ＴＡＧ,产生终止码,阻止ＨＢｅＡｇ合成．后来在许多国家和地区都相继发现了相同的突变株．在我国也有许多关于前Ｃ区突变与慢性肝炎肝硬变有关的报道［６］．这些报道总体上说明１８９６点突变株在毒力上不但比野型株强,而且与野型株有相同的复制和感染能力．我们用双重ＰＣＲ方法对ＨＢＶ感染者血清中ＨＢＶＤＮＡ前Ｃ区１８９６点的突变率进行检测,研究其…     

Salvage therapy using FLT3 inhibitors may improve long‐term outcome of relapsed or refractory AML in patients with FLT3‐ITD

To determine the long‐term efficacy of FLT3 inhibitors (FLT3i) in the salvage setting for relapsed and refractory (rel/ref) acute myeloid leukemia (AML) with FLT3 internal tandem duplication (AML FLT3‐ITD), we conducted a retrospective study of 120 patients with rel/ref AML FLT3‐ITD who received salvage therapy with either FLT3i‐containing regimen (FLT3i group, N = 45) or conventional cytotoxic regimen (conventional group, N = 75). The median overall survival (OS) after the first salvage in the FLT3i group was 6·9 vs. 4·6 months in the conventional group (P = 0·17). The OS was better in the FLT3i group among patients with initial complete remission (CR) duration ≤12 months or with primary refractory disease (6·9 vs. 3·7 months; P < 0·01). The OS was better when FLT3i was combined with cytotoxic agents versus monotherapy (17 vs. 4·8 months; P = 0·017). Multivariate analysis revealed that the use of FLT3i was an independent predictor of OS (hazard ratio 0·58; 95% confidence interval, 0·38–0·88). Incorporating FLT3i into salvage strategies may improve long‐term outcome of patients with AML FLT3‐ITD. Prospective studies to validate this conclusion are warranted.     

The clinical significance of FLT3 ITD mutation on the prognosis of adult acute promyelocytic leukemia

Background and aims: To explore the relationship between FLT3 (encoding Fms related tyrosine kinase 3) internal tandem duplication (ITD) mutations with the prognosis of acute promyelocytic leukemia. The PubMed database, the Cochrane Library, conference proceedings, the EMBASE databases, and references of published trials and review articles were searched. Two reviewers independently assessed the quality of the trials and extracted the data. Odd ratios (ORs) for complete remission (CR) rate after induction therapy, 5-year overall survival (OS), and 5-year disease free survival (DFS) were pooled using the STATA package.

Main results: Seventeen trials involving 2252 patients were ultimately analyzed. The pooled OR showed that the FLT3 ITD mutation group had a poor prognosis in terms of CR rate (OR?=?0.53, 95% confidence interval (CI), 0.30–0.95, P?=?0.03), 5-year OS (OR?=?0.47, 95% CI, 0.29–0.75, P?=?0.002), and as 5-year DFS (OR?=?0.48, 95% CI, 0.29–0.78; p?=?0.003).

Conclusions: The results suggested that FLT3 ITD mutations could become an indicator of poor prognosis of APL, and these patients should receive more intensive therapy according to current guidelines.     

Mutation spectrum of FLT3 and significance of non-canonical FLT3 mutations in haematological malignancy

Fms-like tyrosine kinase 3 (FLT3) is frequently mutated in haematological malignancies. Although canonical FLT3 mutations including internal tandem duplications (ITDs) and tyrosine kinase domains (TKDs) have been extensively studied, little is known about the clinical significance of non-canonical FLT3 mutations. Here, we first profiled the spectrum of FLT3 mutations in 869 consecutively newly diagnosed acute myeloid leukaemia (AML), myelodysplastic syndrome and acute lymphoblastic leukaemia patients. Our results showed four types of non-canonical FLT3 mutations depending on the affected protein structure: namely non-canonical point mutations (NCPMs) (19.2%), deletion (0.7%), frameshift (0.8%) and ITD outside the juxtamembrane domain (JMD) and TKD1 regions (0.5%). Furthermore, we found that the survival of patients with high-frequency (>1%) FLT3-NCPM in AML was comparable to those with canonical TKD. In vitro studies using seven representative FLT3-deletion or frameshift mutant constructs showed that the deletion mutants of TKD1 and the FLT3-ITD mutant of TKD2 had significantly higher kinase activity than wild-type FLT3, whereas the deletion mutants of JMD had phosphorylation levels comparable with wild-type FLT3. All tested deletion mutations and ITD were sensitive to AC220 and sorafenib. Collectively, these data enrich our understanding of FLT3 non-canonical mutations in haematological malignancies. Our results may also facilitate prognostic stratification and targeted therapy of AML with FLT3 non-canonical mutations.     

Sorafenib plus all‐trans retinoic acid for AML patients with FLT3‐ITD and NPM1 mutations

Knowledge of the molecular basis of acute myeloid leukaemia has increased considerably in the past few years, and therapies targeting specific molecular defects of this disease are intensively investigated. Patients with both NPM1 and FLT3‐ITD mutations encompass 20% of cytogenetically normal AML. The multikinase and FLT3 inhibitor, sorafenib, has shown some efficacy in patients with relapsed FLT3‐ITD⁺ AML. In addition, it is suggested that all‐trans retinoic acid (ATRA) used in combination with chemotherapy has shown to improve outcome of patients harbouring NPM1 mutations. We report here the clinical course of three patients with refractory or relapsed FLT3‐ITD⁺/NPM1⁺ AML who achieved significant response upon sorafenib and ATRA combination.     

The genotype nucleophosmin mutated and FLT3‐ITD negative is characterized by high bax/bcl‐2 ratio and favourable outcome in acute myeloid leukaemia

Nucleophosmin gene (NPM1) mutations characterize acute myeloid leukaemia (AML) with normal karyotype and frequently co‐exist with FLT3 internal tandem duplications (ITD). We evaluated bcl‐2, bax, NPM1 and FLT3‐ITD in 222 AML patients. Bax/bcl‐2 ratio >0·35 and NPM1 without FLT3‐ITD were significantly associated (P = 0·0001). NPM1‐mutated (mt)/FLT3‐ITD negative patients showed a higher complete remission (CR) rate (90%, P = 0·0002) and a longer overall survival (OS, P = 0·00007). NPM1‐mt/FLT3‐ITD negative plus bax/bcl‐2 > 0·35 subset showed a very high CR rate (96%), very long OS (P = 0·00005) and disease‐free survival (P = 0·004). The favourable prognosis of NPM1‐mt/FLT3‐ITD negative patients might be explained by a higher bax/bcl‐2 ratio.     

Ponatinib may overcome resistance of FLT3-ITD harbouring additional point mutations, notably the previously refractory F691I mutation

Fms-like tyrosine kinase (FLT3) mutations are the most frequent mutations in patients with acute myeloid leukaemia (AML) that confer a poor prognosis. Constitutively active FLT3-ITD (internal tandem duplications) mutations define a promising target for therapeutic approaches using small molecule inhibitors. However, several point mutations of the FLT3 tyrosine kinase domain (FLT3-TKD) have been identified to mediate resistance towards FLT3 tyrosine kinase inhibitors (FLT3-TKI), including secondary mutations of FLT3. We investigated the cellular effects of the recently characterised FLT3-TKI ponatinib (AP24534) on murine myeloid cells transfected with FLT3-ITD with or without additional point mutations of the FLT3-TKD including the (so far) multi-resistant F691I mutation. Ponatinib effectively induced apoptosis not only in the parental FLT3-ITD cell line but also in all stably transfected subclones harbouring additional FLT3-TKD point mutations (N676D, F691I or G697R). These observations correlated with a strong inhibition of FLT3-ITD and its downstream targets STAT5, AKT and ERK1/2 upon ponatinib incubation, as determined by Western blotting. We conclude that ponatinib represents a promising FLT3-TKI that should be further investigated in clinical trials. The targeted therapy of FLT3-ITD-positive AML with ponatinib might be associated with a lower frequency of secondary resistance caused by acquired FLT3-TKD mutations.