title: [Clinical characteristics and outcomes of lung cancer patients  with EGFR mutations in exons 19 and 21].
abstract: OBJECTIVE
  Studies on the epidermal growth factor receptor (EGFR) signaling pathways and the therapeutic effects of EGFR-tyrosine kinase inhibitors (EGFR-TKIs) have recently proven that targeted therapy has a major role in the treatment of lung cancer. However, the therapeutic effects of EGFR-TKIs on lung cancers with different EGFR mutation subtypes remain unclear. And if there is a significant difference in the effects of EGFR-TKIs, the mechanisms for the difference remain unclear. The aim of this study was to investigate the clinical importance of EGFR mutations in exons 19 and 21 of lung cancer patients and to compare the outcomes of these patients.
  
  
  METHODS
  The study recruited 113 patients who had non-small cell lung cancer (NSCLC) with EGFR mutations. EGFR mutations were detected for 47 patients using Real-time PCR or DNA sequencinag. The mutations of the remaining patients were determined using xTag-EGFR liquid chip technology. All stages I-III patients underwent radical resection followed by 4 cycles of postoperative chemotherapy. Patients with pleural metastases underwent pleural biopsy, pleurodesis, and chemotherapy only. Patients with distant metastases underwent biopsy and chemotherapy only. Collected clinical data were analyzed using SPSS 19.0 software.
  
  
  RESULTS
  EGFR exon mutations 19 and 21 were found in 56 and 57 patients, respectively. The mean age of patients with exon 19 mutations was lower than the age of the patients with exon 21 mutations (57.02±11.31 years vs 62.25±7.76 years, respectively; P<0.05). The primary tumors of patients with exon 19 mutations were more likely occur in the right lung. There were no significant differences in gender, smoking status, histopathology, level of differentiation, and stage of disease (P>0.05) between the patients with exon 19 and 21 mutations; and survival analysis of 91 (80.5%) patients with complete clinical data found no differences in overall survival. Stratification analysis found out that patients with exon 19 mutations had longer overall survival associated with age>61 years, male gender, ever smoking, and stage IV disease; although the differences were not significant.
  
  
  CONCLUSIONS
  Compared to the lung cancer patients with EGFR exon 21 mutations, the patients with EGFR exon 19 mutations were younger, and their primary tumors were more likely to occur in the right lung. There were no significant differences between the lung cancer patients with exon 19 and 21 mutations for overall survival, gender, smoking status, histopathology, level of differentiation, and disease stage.
authors.affiliation: Department of Lung Cancer Surgery, Tianjin Medical University General Hospital, 300052 Tianjin, China.
authors.forename: Renwang
authors.initials: R
authors.lastname: Liu
authors.affiliation: Department of Lung Cancer Surgery, Tianjin Medical University General Hospital, 300052 Tianjin, China.
authors.forename: Jinghao
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Lung Cancer Surgery, Tianjin Medical University General Hospital, 300052 Tianjin, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.affiliation: Tianjin Key Laboratory of Lung Cancer Metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, 300052 Tianjin, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Lung Cancer Surgery, Tianjin Medical University General Hospital, 300052 Tianjin, China.
authors.forename: Qingchun
authors.initials: Q
authors.lastname: Zhao
authors.affiliation: Department of Lung Cancer Surgery, Tianjin Medical University General Hospital, 300052 Tianjin, China.
authors.forename: Zuosheng
authors.initials: Z
authors.lastname: Li
authors.affiliation: Tianjin Key Laboratory of Lung Cancer Metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, 300052 Tianjin, China.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Lung Cancer Surgery;Tianjin Key Laboratory of Lung Cancer Metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, 300052 Tianjin, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
mesh_terms: D000367:Age Factors; D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000196:embryology / Q000235:genetics*; D004252:DNA Mutational Analysis; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D005091:Exons / Q000235:genetics*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009367:Neoplasm Staging; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D047428:Protein Kinase Inhibitors; D066246:ErbB Receptors