Background: Although growth advantage of certain clones would ultimately translate into a clinically visible disease progression, radiological imaging does not reflect clonal evolution at molecular level.Circulating tumor DNA (ctDNA), validated as a tool for mutation detection in lung cancer, could reflect dynamic molecular changes. We evaluated the utility of ctDNA as a predictive and a prognostic marker in disease monitoring of advanced non-small cell lung cancer (NSCLC) patients.Methods: This is a multicenter prospective cohort study. We performed capture-based ultra-deep sequencing on longitudinal plasma samples utilizing a panel consisting of 168 NSCLC-related genes on 949 advanced NSCLC patients with driver mutations to monitor treatment responses and disease progression.The correlations between ctDNA and progression-free survival (PFS)/overall survival (OS) were performed on 248 patients undergoing various treatments with the minimum of 2 ctDNA tests. Results:The results of this study revealed that higher ctDNA abundance (P=0.012) and mutation count (P=8.5×10 −4 ) at baseline are associated with shorter OS. We also found that patients with ctDNA clearance, not just driver mutation clearance, at any point during the course of treatment were associated with longer PFS (P=2.2×10 −16 , HR 0.28) and OS (P=4.5×10 −6 , HR 0.19) regardless of type of treatment and evaluation schedule.Conclusions: This prospective real-world study shows that ctDNA clearance during treatment may serve as predictive and prognostic marker across a wide spectrum of treatment regimens.

Purpose: Clonal architecture is fundamental for the understanding of cancer biology and therapy; however, multiregional sampling in advanced-stage cancers is not always applicable. This prospective clinical trial was to investigate whether paired tissue and circulating tumor DNA (ctDNA) could describe the clonal architecture of advanced non-small cell lung cancer (NSCLC) and its association with clinical outcome (NCT03059641).Patients and Methods: Paired tumor and plasma ctDNA samples were sequenced by target-capture deep sequencing of 1,021 genes. Clonal dominance analysis was performed on the basis of PyClone.Results: Overall, 300 treatment-na€ ve patients with stage IIIB-IV NSCLC were recruited from 14 centers. Of the 94 patients with available ctDNA data for EGFR clonal architecture analysis, 72 (76.6%) showed EGFR as the dominant clone. The median progression-free survival was longer for these patients than for the 22 patients whose EGFR was nondominant clone [11 vs. 10 months; HR, 0.46; 95% confidence interval (CI), 0.24-0.88; P ¼ 0.02]. The difference was more significant if both tissue and ctDNA defined EGFR as dominant clone (n ¼ 43) versus those not (n ¼ 8; 11 vs. 6 months; HR, 0.13; 95% CI, 0.04-0.50; P ¼ 0.003). Moreover, multivariate Cox proportional HR analysis demonstrated EGFR clonal architecture as an independent prognostic indicator of the efficacy of EGFR-tyrosine kinase inhibitors (TKIs).Conclusions: Paired tissue and ctDNA could be analyzed for clonal architecture in advanced cancer. EGFR mutations do not always make up a dominant clone in advanced NSCLC, which was associated with the efficacy of EGFR-TKIs in NSCLC.

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Non–small cell lung cancer (NSCLC) is the main type of lung malignancy. Early diagnosis and treatments for NSCLC are far from satisfactory due to the limited knowledge of the molecular mechanisms regarding NSCLC progression. Long noncoding RNA (lncRNA) ZNFX1 antisense RNA1 (ZFAS1) has been implicated for its functional role in the progression of malignant tumors. This study aimed to determine the ZFAS1 expression from lung cancer clinical samples and to explore the molecular mechanisms underlying ZFAS1‐modulated NSCLC progression. Experimental assays revealed that clinical samples and cell lines of lung malignant tumors showed an upregulation of ZFSA1. ZFAS1 expression was markedly upregulated in the lung tissues from patients with advanced stage of this malignancy. The loss‐of‐function assays showed that knockdown of ZFAS1‐suppressed NSCLC cell proliferative, as well as invasive potentials, increased NSCLC cell apoptotic rates in vitro and also attenuated tumor growth of NSCLC cells in the nude mice. Further experimental evidence showed that ZFAS1 inversely affected miR‐150‐5p expression and positively affected high‐mobility group AT‐hook 2 (HMGA2) expression in NSCLC cell lines. MiR‐150‐5p inhibition or HMGA2 overexpression counteracted the effects of ZFAS1 knockdown on NSCLC cell proliferative, invasive potentials and apoptotic rates. In light of examining the clinical lung cancer samples, miR‐150‐5p expression was downregulated and the HMGA2 expression was highly expressed in the lung cancer tissues compared with normal ones; the ZFAS1 expression showed a negative correlation with miR‐150‐5p expression but a positive correlation with HMGA2 expression in lung cancer tissues. To summarize, we, for the first time, demonstrated the inhibitory effects of ZFAS1 knockdown on NSCLC cell progression, and the results from mechanistic studies indicated that ZFAS1‐mediated NSCLC progression cells via targeting miR‐150‐5p/HMGA2 signaling.

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