BACKGROUND Liquid biopsies of blood plasma cell free DNA can be used to monitor treatment response and potentially detect mutations that are present in resistant clones in metastatic cancer patients. CASE PRESENTATION In our non-interventional liquid biopsy study, a male patient in his fifties diagnosed with stage IV colorectal cancer and polytope liver metastases rapidly progressed after completing chemotherapy and deceased 8 months after diagnosis. Retrospective cell free DNA testing showed that the APC/TP53/KRAS major clone responded quickly after 3 cycles of FOLFIRI + Bevacizumab. Retrospective exome sequencing of pre-chemotherapy and post-chemotherapy tissue samples including metastases confirmed that the APC/TP53/KRAS and other major clonal mutations (GPR50, SLC5A, ZIC3, SF3A1 and others) were present in all samples. After the last chemotherapy cycle, CT imaging, CEA and CA19-9 markers validated the cfDNA findings of treatment response. However, 5 weeks later, the tumour had rapidly progressed. CONCLUSION As FOLFIRI+Bevacizumab has recently also been associated with sustained complete remission in a APC/TP53/KRAS triple-mutated patient, these driver genes should be tested and monitored in a more in-depth manner in future patients. Patients with metastatic disease should be monitored more closely during and after chemotherapy, ideally using cfDNA.

中文翻译：

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具有APC / TP53 / KRAS突变的IV期大肠癌对FOLFIRI和贝伐单抗联合化疗的快速反应：使用液体活检的病例报告。

背景技术无血浆细胞DNA的液体活检可以用于监测治疗反应并潜在地检测转移性癌症患者中抗性克隆中存在的突变。病例介绍在我们的非介入性液体活检研究中，一名五十多岁的男性患者在完成化疗后迅速发展为四期大肠癌和多表位肝转移，并在诊断后8个月死亡。回顾性无细胞DNA测试表明，经过3个FOLFIRI +贝伐单抗循环后，APC / TP53 / KRAS主要克隆快速响应。化疗前和化疗后组织样品（包括转移灶）的回顾性外显子组测序证实，所有样品中均存在APC / TP53 / KRAS和其他主要克隆突变（GPR50，SLC5A，ZIC3，SF3A1等）。在最后一个化疗周期后，CT成像，CEA和CA19-9标记验证了cfDNA对治疗反应的发现。但是，在5周后，肿瘤迅速发展。结论由于FOLFIRI +贝伐单抗最近也与APC / TP53 / KRAS三突变患者的持续完全缓解相关，因此在未来的患者中应更深入地测试和监测这些驱动基因。化疗期间和化疗后，应更密切地监测转移性疾病患者，最好使用cfDNA。这些驱动基因应在未来的患者中进行更深入的测试和监测。化疗期间和化疗后，应更密切地监测转移性疾病患者，最好使用cfDNA。这些驱动基因应在未来的患者中进行更深入的测试和监测。化疗期间和化疗后，应更密切地监测转移性疾病患者，最好使用cfDNA。