伊马替尼治疗后慢性髓系白血病患者ABL激酶区域点突变的检测

Detection of ABL Kinase Domain Point Mutations in Chronic Myeloid Leukemia Patients Receiving Imatinib Treatment

本研究主要探讨甲磺酸伊马替尼(IM)治疗的慢性髓系白血病(CML)患者ABL激酶区点突变的发生情况及其临床意义。应用巢式RT-PCR对328例伊马替尼治疗效果欠佳及10例初诊慢性期CML患者不同时期的51份骨髓标本进行ABL激酶区扩增,并对产物进行纯化、测序以及序列同源性比对,确定点突变的存在及类型。结果显示,12例检出点突变,其类型分别为M351T2例,Q252H7例,E279K1例,E255V及E355G各1例;慢性期、加速期和急变期的点突变发生率分别为17.6%(3/17)、45.5%(5/11)和44.4%(4/9);血液学和遗传学耐药患者的点突变发生率分别为50%(5/10)和44.4%(8/18),其95%的可信区间分别为12.3%-87.7%和19%-69.9%;有点突变的12例患者的疗效均欠佳,经过加量至600m g,随访3-24个月,在治疗过程中均出现疾病进展或死亡。结论:ABL激酶区点突变是伊马替尼耐药导致CML治疗失败的一个重要原因,监测点突变的发生及其类型有助于早期进行疾病预后评估及调整治疗方案。

This study was purposed to evaluate ABL tyrosine kinase point mutations in imatinib-treated chronic myeloid leukemia （CML） patients and thief clinical significance. 51 bone marrow samples from 28 imatinib-resistant patients and 10 newly diagnosed CML patients were collected. ABL kinase domain of bcr-abl allele was amplified by nested reverse transcription-polymerase chain reaction, followed by purifying, directly sequencing and sequence homology analysis of amplified products in order to determine the existence and type of point mutation. The results showed that the point mutations were found in 12 of 38 patients, and all the 12 ones progressed to advanced disease or death. 2 patients showed Met351Thr mutation, 7 patients showed Glu252His, 2 patients showed Glu279Lys, the other types were Glu255Val and Glu355Gly,each of which was tested in one patient. The incidence of the point mutation was 17.6%, 45.5% and 44. 4% in chronic, accelerated and blast phase respectively. The incidences of point mutatim in hematologically and genetically resistant patients were 50% （5/10）and 44.4% （8/18）, and the 95% confidence interval （CI） was 12.3% -87.7% and 19% -69.9% respectively. It is concluded that ABL kinase point mutation is an important mechanism of imatinib resistance, monitoring the ABL kinase domain point mutation is helpful to estimating the prognosis and adjusting the therapeutic strategy.