Abstract：
Highly polymorphic BCR-ABL kinase domains have been reported to harbor more than a hundred mutations, and among these, 40-60% have been identified as influencers of imatinib mesylate (IM) resistance. The emergence of IM resistance poses a significant challenge in the management of Chronic Myeloid Leukemia (CML). M351T (rs121913457), E255K (rs387906517), and Y253H (rs121913461) are of particular clinical significance due to their association with high-level imatinib resistance. This study was conducted to investigate the potential role of three significant SNPs in CML progression due to IM resistance. During the study period from 2018 to 2022 (48 months), the blood samples from 219 Reverse transcriptase-PCR-confirmed CML patients following RNA extraction and cDNA preparation were subjected to M351T, E255K, and Y253H mutation analysis by PCR-RFLP. After agarose gel visualization, the samples were subjected to Sanger sequencing to confirm the nucleotide change at the polymorphic loci. The wild-type genotype of all three ABL1 SNPs under investigation exhibits a significant reduction in frequency among IM non-responders compared to the responder group. The CGT haplotype frequency exhibits a significant difference between IM responder (4.2%) and non-responder (11.8%) (p = 0.002 < 0.05). Further, CGC haplotype was observed solely among the imatinib non-responder patients with a frequency percentage of 3.3% (p = 0.004), whereas the said genotype was absent among the responder group. A reduced overall survival rate was observed with deviation from wild-type genotype (M351T loci (T > C) with 1.217 times, E255K (G > A) with 1.485 and Y253H (T > C) with 1.399 times increase in hazard ratio) thereby enhancing mortality risk due to disease progression. The significant increase in the frequency of M351T, E255K, and Y253H loci among the IM non-responder group indicated their probable association with the development of IM resistance among CML patients. A haplotype frequency distribution pattern analysis of ABL1 loci further identified the CGC haplotype as an independent predictor for IM resistance. As such the study highlights the importance of patient characteristics, genotype distribution, and haplotype frequency distribution in predicting the response to IM treatment and clinical outcomes of CML patients.
摘要：
据报道，高度多态的BCR-ABL激酶结构域含有一百多个突变，其中，40-60%已被确定为甲磺酸伊马替尼(IM)耐药性的影响者。IM耐药性的出现对慢性髓性白血病（CML）的治疗提出了重大挑战。M351T(rs121913457),E255K(rs387906517),和Y253H(rs121913461)由于与高水平的伊马替尼耐药相关,因此具有特别的临床意义.进行这项研究以研究由于IM抗性导致的三个重要SNP在CML进展中的潜在作用。在2018年至2022年（48个月）的研究期间，在RNA提取和cDNA制备后，对219例逆转录-PCR证实的CML患者的血液样本进行M351T，E255K,并通过PCR-RFLP分析Y253H突变。琼脂糖凝胶可视化后，对样品进行Sanger测序以确认多态性位点的核苷酸变化。与应答者组相比,所研究的所有三种ABL1SNP的野生型基因型在IM非应答者中表现出频率的显著降低。CGT单倍型频率在IM应答者(4.2%)和非应答者(11.8%)之间表现出显著差异(p=0.002<0.05)。Further,仅在伊马替尼无反应患者中观察到CGC单倍型，频率百分比为3.3％（p=0.004），而所述基因型在应答者组中不存在。与野生型基因型(M351T位点(T>C)的差异为1.217倍,E255K（G>A）的1.485和Y253H（T>C）的风险比增加1.399倍），从而增加了由于疾病进展而导致的死亡风险。M351T的频率显著增加，E255K,IM无应答者组中的Y253H基因座表明它们可能与CML患者IM耐药的发展有关。ABL1基因座的单倍型频率分布模式分析进一步鉴定了CGC单倍型作为IM抗性的独立预测因子。因此，这项研究强调了患者特征的重要性，基因型分布，和单倍型频率分布在预测CML患者对IM治疗的反应和临床结局方面的作用。
