Author of

• 18974

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  P3.02 - Biology/Pathology (ID 620)

  • Event: WCLC 2017
  • Type: Poster Session with Presenters Present
  • Track: Biology/Pathology
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)

  • 23956

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    P3.02-009 - Mutation Detection in Cell-Free DNA from Patients with Lung Adenocarcinoma by Next-Generation Sequencing (ID 9308)

    09:30 - 09:30  |  Author(s): Y. Horimasu
    • Abstract

    Background:
    Cell-free DNA (cfDNA) is an alternative non-invasive source to assess gene mutations which are necessary for precision medicine in cancer patients. Next-generation sequencing (NGS) can list multiple gene mutations in single testing and require low input of DNA. We evaluated NGS application to detect cfDNA mutations in lung adenocarcinoma (LAC).
    
    Method:
    Retrospectively, cfDNA was isolated from 12 LAC patients in Hiroshima University Hospital (first group). Then another cfDNA was isolated from 30 LAC patients (second group). Ion PGM AmpliSeq system was applied using two panels, Cancer Hotspot (50 genes) for first group and Colon and Lung Cancer Research (22 genes) for second group. Variants were manually reviewed. EGFR mutation in cfDNA and tumor DNA (tDNA) were matched. EGFR mutations in tDNA, derived from either cytology or biopsy specimen, were previously analysed using PNA-clamp PCR.
    
    Result:
    Stage were 1 IIA, 1 IIIA and 10 IV in first group and 3 IA, 7 IB, 3 IIIA and 17 IV in second group. Mean coverage in first and second group were 863 and 2915, respectively. Mutation were found in TP53 (33/42), EGFR (8/42), STK11 (5/42), PTEN (3/42), ERBB4 (2/42), SMAD4 (2/42), MET (2/42), KDR (8/12), APC (4/12), RB1 (2/12), GNAQ (1/12), KIT (1/12), MLH1 (1/12), RET (2/12), VHL (1/12), KRAS (1/42). KRAS (A146V) mutated in one patient with no EGFR mutation detected in tDNA. In first group, EGFR mutations from tDNA were identified in 5 of 12 patients. Concordant EGFR mutations between cfDNA and tDNA were found in 1 of 5 patients (Exon 19 deletion, Allele Frequency, AF 9.1% (11/121)). In second group, EGFR mutations from tDNA were identified in 15 of 30 patients. Concordant EGFR mutations between cfDNA and tDNA were found in 7 of 15 patients. AF in EGFR exon 19 deletion were 0.1% (3/2424), 0.2% (6/2973), 8% (272/3394) and 24% (470/1960) and in exon 21 mutations were 2% (61/3884), 0.3% (5/1702) and 57% (1711/3025). The sensitivity and specificity in first and second group were 25%, 100% and 40%, 100%, respectively. In both group, patients whose EGFR mutations were detected in both tDNA and cfDNA were all in stage IV.
    
    Conclusion:
    NGS using cfDNA is less invasive method to detect various mutations simultaneously, especially in advance stage. EGFR mutation detection in cfDNA by NGS achieved a high specificity. Reducing target genes or deep sequencing may increase the sensitivity of detecting mutations.