Recently, liquid biopsy, as a promising approach was introduced for the analysis of different tumor-derived circulating markers including tumor DNA and cell free DNA (ct/cfDNA). Identification of mutations in cfDNA may allow the early detection of tumors, as well as predicting and monitoring treatment responses in a minimally invasive way. In the present study, we used commercially available gene panels to verify the mutation overlap between liquid biopsy and abnormalities detected in colorectal tumor tissue. The two panels (Archer®VariantPlex®Solid Tumor and LIQUIDPlexTM ctDNA) overlap in 23 genes, which enables a comprehensive view of tumor-plasma mutational status by next generation sequencing. We successfully analyzed 16 plasma and 16 tumor samples. We found that 87% of tumor tissues contained 44 mutations in 12 genes and 43.8% of cfDNA harbored 13 mutations in 5 genes. To verify whether the mutation pattern of the tumor DNA could be consistently detected in plasma cfDNA, we compared the alterations between cfDNA and matched tissue DNA in nine patients. Six of the 9 tumor tissues harbored mutations in TP53, KRAS or MET genes, those were not detectable by the ctDNA kit, even eventhough the exons of these genes overlap in both panels. Comparing the mutational patterns of the matched samples, we found that only one cfDNA had the same mutations (KRAS, SMAD4 and TP53) in the paired tissue. The results of the comparison between tumor tissue DNA and matched plasma cfDNA underline the importance of studying the paired solid tumor and plasma samples together.

最近，液体活检作为一种有前途的方法被引入用于分析不同肿瘤来源的循环标志物，包括肿瘤 DNA 和无细胞 DNA (ct/cfDNA)。鉴定 cfDNA 中的突变可能有助于早期发现肿瘤，并以微创方式预测和监测治疗反应。在本研究中，我们使用市售的基因组来验证液体活检与结直肠肿瘤组织中检测到的异常之间的突变重叠。这两个 panel（Archer®VariantPlex®Solid Tumor 和 LIQUIDPlexTM ctDNA）在 23 个基因中重叠，这使得通过下一代测序能够全面了解肿瘤-血浆突变状态。我们成功分析了 16 份血浆和 16 份肿瘤样本。我们发现 87% 的肿瘤组织在 12 个基因和 43 个基因中包含 44 个突变。8% 的 cfDNA 在 5 个基因中存在 13 个突变。为了验证是否可以在血浆 cfDNA 中始终检测到肿瘤 DNA 的突变模式，我们比较了 9 名患者的 cfDNA 和匹配组织 DNA 之间的变化。9 个肿瘤组织中有 6 个在TP53、KRAS或MET基因，ctDNA 试剂盒无法检测到这些基因，即使这些基因的外显子在两个面板中重叠。比较匹配样本的突变模式，我们发现配对组织中只有一个 cfDNA 具有相同的突变（KRAS、SMAD4和TP53 ）。肿瘤组织 DNA 和匹配的血浆 cfDNA 之间的比较结果强调了一起研究配对的实体瘤和血浆样本的重要性。