title: [Relevance of circulating tumor DNA in lung cancer: A case report].
abstract: BACKGROUND
  The identification of an activating mutation of the gene encoding the epidermal growth factor receptor (EGFR) is a predictive factor of effectiveness of tyrosine kinase EGFR inhibitors (TKIs). In advanced stages of the disease, however, this identification is difficult due to the invasiveness of the biopsy and the small size of tumor samples. In that context, liquid biopsies could be useful.
  
  
  METHODS
  We report the case of a 79-year-old woman suffering from metastatic lung cancer. The molecular analysis of bronchial biopsy for the EGFR gene was not informative due to the low quantity and the poor quality of the extracted DNA. The poor condition of the patient and her refusal to tissue sampling did not allow us to practice another invasive biopsy. The analysis of the tumor DNA circulating (cDNA) allowed to detect exon 19 deletion and to propose her an TKI with in the outcome sustained response.
  
  
  CONCLUSIONS
  Circulating DNA analysis allows the identification of activating mutations of the EGFR gene in pulmonary adenocarcinomas. It is useful for weakened patients and in case of failure or inability of tumor biopsies. Initiation of EGFR TKI is possible on the basis of this result, as stated in the marketing authorization of gefitinib.
authors.affiliation: Institut de cancérologie et d'hématologie, hôpital Augustin-Morvan, CHRU de Brest, 2, avenue du Maréchal-Foch, 29000 Brest, France. Electronic address: aamranekarim@gmail.com.
authors.forename: K
authors.initials: K
authors.lastname: Amrane
authors.affiliation: Plateforme de génétique moléculaire des cancers, laboratoire de génétique moléculaire et histocompatibilité, CHRU de Brest, 29000 Brest, France.
authors.forename: G
authors.initials: G
authors.lastname: Le Gac
authors.affiliation: Institut de cancérologie et d'hématologie, hôpital Augustin-Morvan, CHRU de Brest, 2, avenue du Maréchal-Foch, 29000 Brest, France.
authors.forename: R
authors.initials: R
authors.lastname: Descourt
authors.affiliation: Institut de cancérologie et d'hématologie, hôpital Augustin-Morvan, CHRU de Brest, 2, avenue du Maréchal-Foch, 29000 Brest, France.
authors.forename: G
authors.initials: G
authors.lastname: Quere
mesh_terms: D000230:Adenocarcinoma / Q000097:blood* / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D000077192:Adenocarcinoma of Lung; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000097:blood; D004273:DNA, Neoplasm / Q000032:analysis / Q000097:blood*; D066246:ErbB Receptors / Q000235:genetics; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood* / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D009362:Neoplasm Metastasis; D011237:Predictive Value of Tests; D011379:Prognosis; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D047428:Protein Kinase Inhibitors; C512478:EGFR protein, human; D066246:ErbB Receptors
keywords: ADN circulant; Adenocarcinoma; Adénocarcinome; Cancer bronchique non à petites cellules; Circulating DNA; Epidermal growth factor receptor; Erlotinib; Non-small cell lung cancer; Récepteur à l’EGFR