Noriko Hidaka1, Eiji Iwama2, Naoki Kubo3, Taishi Harada1, Kohta Miyawaki4, Kentaro Tanaka1, Isamu Okamoto1, Eishi Baba5, Koichi Akashi4, Hiroyuki Sasaki6, Yoichi Nakanishi1. 1. Research Institute for Diseases of the Chest, Graduate School of Medical Sciences, Kyushu University, Fukuoka 8128582, Japan. 2. Research Institute for Diseases of the Chest, Graduate School of Medical Sciences, Kyushu University, Fukuoka 8128582, Japan; Department of Comprehensive Clinical Oncology, Faculty of Medical Sciences, Kyushu University, Fukuoka 8128582, Japan. Electronic address: iwama@kokyu.med.kyushu-u.ac.jp. 3. Research Institute for Diseases of the Chest, Graduate School of Medical Sciences, Kyushu University, Fukuoka 8128582, Japan; Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, Fukuoka 8128582, Japan. 4. Department of Medicine and Biosystemic Science, Kyushu University Graduate School of Medical Sciences, Fukuoka 8128582, Japan. 5. Department of Comprehensive Clinical Oncology, Faculty of Medical Sciences, Kyushu University, Fukuoka 8128582, Japan. 6. Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, Fukuoka 8128582, Japan.
Abstract
OBJECTIVES: The T790M and C797S mutations of the epidermal growth factor receptor gene (EGFR) confer resistance to first- and third-generation EGFR tyrosine kinase inhibitors (TKIs), respectively, in patients with non-small cell lung cancer (NSCLC) harboring activating mutations of EGFR. C797S has been identified in cis or in trans with T790M in tumor specimens from patients who experienced treatment failure with first- and third-generation EGFR-TKIs. The allelic relation between T790M and activating mutations of EGFR has not been well characterized, however. We have now developed a digital polymerase chain reaction (dPCR)-based method for determination of the allelic relation between two types of EGFR mutation (T790M and either C797S or an activating mutation). MATERIALS AND METHODS: Seven clinical NSCLC specimens and two NSCLC cell lines harboring both an activating mutation and T790M were analyzed with this new method to identify the allelic relation between these EGFR mutations. RESULTS: The median ratio of the number of alleles positive for both an activating mutation and T790M to the number of T790M-positive alleles was 97.1% (range, 90.0-100%). Confirmatory analysis by next-generation sequencing yielded a corresponding value of 96.7% (range, 89.1-99.5%). Our dPCR method thus reliably identifies the allelic relation between two EGFR mutations in a quantitative manner. CONCLUSIONS: Almost all T790M mutations were detected in cis with activating mutations of EGFR regardless of the de novo or acquired status of T790M, with cancer cells harboring T790M and activating mutations on the same allele appearing to be selected and enriched during EGFR-TKI treatment.
OBJECTIVES: The T790M and C797S mutations of the epidermal growth factor receptor gene (EGFR) confer resistance to first- and third-generation EGFR tyrosine kinase inhibitors (TKIs), respectively, in patients with non-small cell lung cancer (NSCLC) harboring activating mutations of EGFR. C797S has been identified in cis or in trans with T790M in tumor specimens from patients who experienced treatment failure with first- and third-generation EGFR-TKIs. The allelic relation between T790M and activating mutations of EGFR has not been well characterized, however. We have now developed a digital polymerase chain reaction (dPCR)-based method for determination of the allelic relation between two types of EGFR mutation (T790M and either C797S or an activating mutation). MATERIALS AND METHODS: Seven clinical NSCLC specimens and two NSCLC cell lines harboring both an activating mutation and T790M were analyzed with this new method to identify the allelic relation between these EGFR mutations. RESULTS: The median ratio of the number of alleles positive for both an activating mutation and T790M to the number of T790M-positive alleles was 97.1% (range, 90.0-100%). Confirmatory analysis by next-generation sequencing yielded a corresponding value of 96.7% (range, 89.1-99.5%). Our dPCR method thus reliably identifies the allelic relation between two EGFR mutations in a quantitative manner. CONCLUSIONS: Almost all T790M mutations were detected in cis with activating mutations of EGFR regardless of the de novo or acquired status of T790M, with cancer cells harboring T790M and activating mutations on the same allele appearing to be selected and enriched during EGFR-TKI treatment.
Authors: Alexander N Gorelick; Francisco J Sánchez-Rivera; Yanyan Cai; Craig M Bielski; Evan Biederstedt; Philip Jonsson; Allison L Richards; Neil Vasan; Alexander V Penson; Noah D Friedman; Yu-Jui Ho; Timour Baslan; Chaitanya Bandlamudi; Maurizio Scaltriti; Nikolaus Schultz; Scott W Lowe; Ed Reznik; Barry S Taylor Journal: Nature Date: 2020-05-27 Impact factor: 69.504