摘要标题：血浆cfDNA对经TACE治疗的肝癌患者残癌复发的早期预警价值

Background: Hepatocellular carcinoma (HCC) is one of the most common prevalent fatal cancers worldwide with poor prognosis due to high incidence of recurrence. For patients with advanced HCC, transcatheter arterial chemoembolization (TACE), a minimal invasive clinical nonsurgical treatment is the standard first-line option. However, current surveillance approaches based on serological examination (including AFP) and imaging (ultrasound, CT, MRI, etc.) are limited in early detection of residual cancer and relapse that result in the bottleneck of long-term effects after TACE therapy. 

研究背景：肝细胞癌(HCC)是世界范围内最常见的恶性肿瘤之一，由于复发率高预后较差。对于晚期肝癌患者，微创型经导管动脉化疗栓塞术(TACE)治疗是标准的一线选择。然而，目前基于血清学检查(包括AFP)和影像学检查(超声、CT、MRI等)的监测方法在早期发现残癌复发方面存在局限性，这导致了TACE治疗后长期效果的瓶颈。

Methods: This study consists of two parts. In the first part, forty-one patients with HCC were included. According to number of tumor lesions, patients were classified into two groups: single lesion group (S) and multiple lesions group (M). In the second part, three patients with advanced HCC treated with TACE were included. Periodic evaluation of plasma cfDNA together with radiologic examination, laboratory testing (including AFP) were performed simultaneously to trace the dynamic response of HCC patients after TACE treatment. Tumor tissue DNA and matching cell-free DNA are subjected to enrichment for a 1.15M size panel covering exon regions of 1,086 genes. With next generation sequencing on an Illumina X10 platform, the captured sequencing data was further processed using bioinformatics analysis to identify somatic mutations, including single nucleotide variants (SNV), short insertions/deletions (indels) and copy number variations (CNVs).

研究方法：本研究由两部分组成。第一部分纳入41例HCC患者。根据肿瘤病灶的数量，将患者分为两组：单一病灶组(S)和多发性病灶组(M)。第二部分纳入3例经TACE治疗的晚期肝癌患者。将患者血浆cfDNA与影像学检查、实验室检测(包括AFP)的定期评估同时进行，以追踪TACE治疗后HCC患者的动态病情变化。提取肿瘤组织DNA和配对的血浆的cfDNA，富集1086个基因的1.15M的外显子区域。以NGS测序法结合生物信息学，全面解析特定基因变异、单核苷酸多态性、插入缺失突变、拷贝数变异等指标。

Result: We showed that the mutational profiles of plasma cfDNA is in consistency with that of tumor tissue DNA. Using the mutation burden of 7 genes (CTNNB1, PIK3CA, MET, EGFR, FBXMW7, TP53, and ERBB2.), the M group can be distinguished from S group. In addition, plasma cfDNA mutation burden of 10 genes (NRAS, BRAF, PIK3CA, KRAS, ARID1A, AXIN1, ARID2, TERT, TP53, CTNNB1) indicates relapse weeks prior to conventional computed tomography (CT) imaging and Alpha-Fetoprotein (AFP) changes.

研究结果：我们发现血浆cfDNA的突变谱与肿瘤组织DNA的突变谱是一致的。可以通过7个基因的突变负荷(CTNNB1, PIK3CA, MET, EGFR, FBXMW7, TP53, ERBB2)来区分M组与S组的患者。此外，血浆cfDNA中10个基因的突变负荷(NRAS、BRAF、PIK3CA、KRAS、ARID1A、AXIN1、ARID2、TERT、TP53、CTNNB1)的变化早于常规影像学 CT和甲胎蛋白(AFP)改变数周提早预示残癌复发。

Conclusion: Our results suggest that plasma cfDNA serves as a promising surveillance tool of HCC patients treated with TACE. The high mutation burden status of 10 genes (NRAS, BRAF, PIK3CA, KRAS, ARID1A, AXIN1, ARID2, TERT, TP53, CTNNB1) might correlate with recurrence in HCC patients.

研究结论：我们的研究结果表明，血浆cfDNA对经TACE治疗的肝癌患者是很有前景的监测指标。10个基因的高突变负荷状态(NRAS, BRAF, PIK3CA, KRAS, ARID1A, AXIN1, ARID2, TERT, TP53, CTNNB1)可能与HCC患者的复发相关。