ABSTRACT

The mutation status of KRAS is important for anti-EGFR therapy in colorectal cancer (CRC) patients; however, detection of KRAS mutations in circulating tumor DNA (ctDNA) is problematic. We investigated tissue and plasma assays for KRAS mutations in CRC patients. The KRAS status of 407 CRC patients was evaluated using integration of amplification refractory mutation system polymerase chain reaction (PCR), melting curves and wild type DNA blocking (IAMB) in tissue and plasma samples. Disparate cases were re-evaluated by Sanger sequencing of tissue samples. General characteristics and tumor biomarkers including CEA, CA19-9 and CA125 were characterized. The prevalence of KRAS mutations was 40.8% in plasma and 49.1% in tissue. The overall percent agreement, positive percent agreement and negative percent agreement were 82.3, 76.3 and 90.8%, respectively. Older patients and higher TNM stage exhibited increased sensitivity for detecting KRAS mutations in plasma. We found 54.1% of patients with KRAS mutations using parallel analysis of tissue and plasma; only 36.4% of patients were detected by series analysis. We found that plasma based KRAS detection with IAMB technology is an alternative to tissue based KRAS testing. KRAS mutations can be identified more easily when both assays are used together

摘要

KRAS的突变状态对于结直肠癌（CRC）患者的抗EGFR治疗很重要；然而，检测循环肿瘤 DNA (ctDNA) 中的KRAS突变是有问题的。我们研究了 CRC 患者中KRAS突变的组织和血浆检测。使用扩增难治性突变系统聚合酶链反应 (PCR)、熔解曲线和组织和血浆样本中的野生型 DNA 封闭 (IAMB) 的整合评估 407 名 CRC 患者的KRAS状态。不同的病例通过组织样本的 Sanger 测序重新评估。表征了一般特征和肿瘤生物标志物，包括 CEA、CA19-9 和 CA125。KRAS的流行血浆中的突变为 40.8%，组织中为 49.1%。总体一致性百分比、正百分比一致性和负百分比一致性分别为 82.3、76.3 和 90.8%。年龄较大的患者和较高的 TNM 分期表现出检测血浆中KRAS突变的敏感性增加。我们使用组织和血浆的平行分析发现了 54.1% 的KRAS突变患者；通过系列分析仅检测到 36.4% 的患者。我们发现采用 IAMB 技术的基于血浆的KRAS检测是基于组织的KRAS检测的替代方案。当两种检测方法一起使用时，可以更容易地识别KRAS突变