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MA 07 - ALK, ROS and HER2 (ID 673)
- Event: WCLC 2017
- Type: Mini Oral
- Track: Advanced NSCLC
- Presentations: 1
MA 07.13 - NGS Sequencing Based Liquid / Tissue Biopsy Identified Coexistence of HER2 Amplification and Mutation in Advanced NSCLC Patients (ID 9737)
15:45 - 17:30 | Author(s): Xinghao Ai
Human epidermal growth factor 2 (HER2, ERBB2) mutations / amplifications have been identified as oncogenic drivers in 2-5% of lung cancers. It has been reported that hybridization capture-based next-generation sequencing (NGS) could reliably detect HER2 amplification in qualified breast and gastroesophageal tumor tissue samples. However, there is little data in lung cancer, especially for advance NSCLC with only ctDNA samples available.
We reviewed 2000 consecutive samples from advanced NSCLC patients sequenced in our institute between 2015 and 2016. Tumor biopsy and/or ctDNA samples were analyzed using hybridization capture-based NGS ER-Seq method, which enables simultaneously assess single-nucleotide variants, insertions/deletions, rearrangements, and somatic copy-number alterations at least 59 genes (range 59 – 1021 genes).
We identified 54 samples from 48 patients with HER2-mutation or amplification in the cohort (54/2000=2.7%). The 54 samples included 14 tissue biopsy samples, 37 ctDNA samples, and 3 pleural effusion samples. Thirty-six samples carried HER2 mutations, and 23 samples carried HER2 amplification with 5 samples have concurrent HER2 mutation and amplification. A 9-base pair (bp) in-frame insertion in exon 20 (Y772_A775dup) was detected in 18 samples (18/36=50%). In addition, there were 5 other insertions in exon 20; eight single bp substitutions (S310F) in exon 8; three exon 17 V659E mutations (from the sample patient with 3 ctDNA samples submitted at different time); one exon 19 D769H mutation; and one exon 21 V842I mutation. Amplification were identified in 23 samples, with copy number range from 3.8 to 19.6 in tissue samples (n=7, medium 11.6); from 4.3 to 51.8 in ctDNA samples (n=16, medium 7.3); 3.2 and 6 in the 2 pleural effusion samples. Interestingly, the allele frequency (AF) of HER2 mutation was the maximal in 4 of the 5 patients with concurrent HER2 mutation and amplification. Two patients were EGFR-TKI resistant with EGFR L858R mutation remaining and HER2 mutation and amplification might be the major reason for the resistance.
HER2 mutations might coexist with HER2 amplification in advanced NSCLC patients, and it could be detected simultaneously with hybridization capture-based NGS sequencing both in tissue and liquid biopsy samples. Further quantative analysis of HER2 amplification / mutation and anti-HER2 therapeutic effects are underway.
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