Lee Jong Won, Park Young Soo, Choi Jung Yoon, Chang Won Jin, Lee Soohyeon, Sung Jae Sook, Kim Boyeon, Lee Saet Byeol, Lee Sung Yong, Choi Jungmin, Kim Yeul Hong
Cancer Research Institute, Korea University College of Medicine, Seoul, South Korea.
Brain Korea 21 Plus Project for Biomedical Science, Korea University College of Medicine, Seoul, South Korea.
Front Oncol. 2022 Mar 24;12:843561. doi: 10.3389/fonc.2022.843561. eCollection 2022.
Circulating cell-free DNA (cfDNA) can be used to characterize tumor genomes through next-generation sequencing (NGS)-based approaches. We aim to identify novel genetic alterations associated with drug resistance in lung cancer and colorectal cancer patients who were treated with EGFR-targeted therapy and cytotoxic chemotherapy through whole exome sequencing (WES) of cfDNA. A cohort of 18 lung cancer patients was treated with EGFR TKI or cytotoxic chemotherapy, and a cohort of 37 colorectal cancer patients was treated with EGFR monoclonal antibody or cytotoxic chemotherapy alone. Serum samples were drawn before and after development of drug resistance, and the genetic mutational profile was analyzed with WES data. For 110 paired cfDNA and matched germline DNA WES samples, mean coverage of 138x (range, 52-208.4x) and 47x (range, 30.5-125.1x) was achieved, respectively. After excluding synonymous variants, mutants identified in more than two patients at the time of acquired resistance were selected. Seven genes in lung cancer and 16 genes in colorectal cancer were found, namely, APC, TP53, KRAS, SMAD4, and EGFR. In addition, the GPR155 I357S mutation in lung cancer and ADAMTS20 S1597P and TTN R7415H mutations in colorectal cancer were frequently detected at the time of acquired resistance, indicating that these mutations have an important function in acquired resistance to chemotherapy. Our data suggest that novel genetic variants associated with drug resistance can be identified using cfDNA WES. Further validation is necessary, but these candidate genes are promising therapeutic targets for overcoming drug resistance in lung cancer and colorectal cancer.
循环游离DNA（cfDNA）可通过基于下一代测序（NGS）的方法用于表征肿瘤基因组。我们旨在通过对cfDNA进行全外显子组测序（WES），在接受表皮生长因子受体（EGFR）靶向治疗和细胞毒性化疗的肺癌和结直肠癌患者中，鉴定与耐药性相关的新基因改变。18例肺癌患者接受了EGFR酪氨酸激酶抑制剂（TKI）或细胞毒性化疗，37例结直肠癌患者仅接受了EGFR单克隆抗体或细胞毒性化疗。在出现耐药性之前和之后采集血清样本，并利用WES数据分析基因变异谱。对于110对cfDNA和匹配的种系DNA WES样本，平均覆盖度分别达到138倍（范围52 - 208.4倍）和47倍（范围30.5 - 125.1倍）。排除同义变异后，选择在获得性耐药时在两名以上患者中鉴定出的突变体。在肺癌中发现了7个基因，在结直肠癌中发现了16个基因，即腺瘤性息肉病基因（APC）、肿瘤蛋白p53（TP53）、 Kirsten大鼠肉瘤病毒癌基因（KRAS）、SMAD家族成员4（SMAD4）和表皮生长因子受体（EGFR）。此外，在获得性耐药时，肺癌中的G蛋白偶联受体155（GPR155）I357S突变以及结直肠癌中的含血小板反应蛋白基序的解聚蛋白样金属蛋白酶20（ADAMTS20）S1597P和肌联蛋白（TTN）R7415H突变经常被检测到，表明这些突变在化疗获得性耐药中具有重要作用。我们的数据表明，使用cfDNA WES可以鉴定与耐药性相关的新基因变异。进一步验证是必要的，但这些候选基因有望成为克服肺癌和结直肠癌耐药性的治疗靶点。
