Quantification and dynamic monitoring of EGFR T790M in plasma cell-free DNA by digital PCR for prognosis of EGFR-TKI treatment in advanced NSCLC

• Published in: PloS one 2014-11, Vol.9 (11), p.e110780
• Main Authors: Wang, Zhijie, Chen, Rui, Wang, Shuhang, Zhong, Jia, Wu, Meina, Zhao, Jun, Duan, Jianchun, Zhuo, Minglei, An, Tongtong, Wang, Yuyan, Bai, Hua, Wang, Jie
• Format: Article
• Language: English
• Subjects: Adult; Aged; Amplification; Antineoplastic Agents - pharmacology; Antineoplastic Agents - therapeutic use; Biomarkers, Tumor - blood; Biomarkers, Tumor - genetics; c-Met protein; Cancer therapies; Carcinoma, Non-Small-Cell Lung - blood; Carcinoma, Non-Small-Cell Lung - drug therapy; Chromatography; Clinical outcomes; Deoxyribonucleic acid; DNA; Drug Resistance, Neoplasm - genetics; Education; Epidermal growth factor; Epidermal growth factor receptors; Female; Genetic testing; High performance liquid chromatography; Humans; Kinases; Laboratories; Liquid chromatography; Lung cancer; Lung diseases; Lung Neoplasms - blood; Lung Neoplasms - drug therapy; Male; Medical prognosis; Medical research; Medicine and Health Sciences; Middle Aged; Mutation; Mutation, Missense; Non-small cell lung cancer; Non-small cell lung carcinoma; Oncology; Patients; Plasma; Polymerase chain reaction; Prognosis; Protein Kinase Inhibitors - pharmacology; Protein Kinase Inhibitors - therapeutic use; Protein-tyrosine kinase; Receptor, Epidermal Growth Factor - antagonists & inhibitors; Receptor, Epidermal Growth Factor - blood; Receptor, Epidermal Growth Factor - genetics; Resistance factors; Survival; Therapy; Tumors; Tyrosine
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0110780

Among advanced non-small cell lung cancer (NSCLC) patients with an acquired resistance to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI), about 50% carry the T790M mutation, but this frequency in EGFR-TKI-naïve patients and dynamic change during therapy remains unclear. This study investigated the quantification and dynamic change of T790M mutation in plasma cell-free DNA (cf-DNA) of advanced NSCLC patients to assess the clinical outcomes of EGFR-TKI therapy. We retrospectively investigated 135 patients with advanced NSCLC who obtained progression-free survival (PFS) after EGFR-TKI for >6 months for their EGFR sensitive mutations and T790M mutation in matched pre- and post-TKI plasma samples, using denaturing high-performance liquid chromatography (DHPLC), amplification refractory mutation system (ARMS), and digital-PCR (D-PCR). Real-time PCR was performed to measure c-MET amplification. Detection limit of D-PCR in assessing the T790M mutation was approximately 0.03%. D-PCR identified higher frequency of T790M than ARMS in pre-TKI (31.3% vs. 5.5%) and post-TKI (43.0% vs. 25.2%) plasma samples. Patients with pre-TKI T790M showed inferior PFS (8.9 vs. 12.1 months, p = 0.007) and overall survival (OS, 19.3 vs. 31.9 months, p = 0.001) compared with those without T790M. In patients harboring EGFR sensitive mutation, high quantities of pre-TKI T790M predicted poorer PFS (p = 0.001) on EGFR-TKI than low ones. Moreover, patients who experienced increased quantity of T790M during EGFR-TKI treatment showed superior PFS and OS compared with those with decreased changes (p = 0.044 and p = 0.015, respectively). Qualitative and quantitative T790M in plasma cf-DNA by D-PCR provided a non-invasive and sensitive assay to predict EGFR-TKI prognosis.