title: Correlation study and significance of the EGFR expression in serum, lymph nodes and tumor tissue of NSCLC.
abstract: BACKGROUND
  This study was designed to detect the protein expression of epidermal growth factor receptor (EGFR) among serum, lymph node, and tumor tissues, and to discuss their relationship and clinical significance. We investigated whether EGFR levels in serum and lymph nodes could be used as an effective method for non-small cell lung cancer (NSCLC) to diagnose and assess clinical stage.
  
  
  METHODS
  In 56 patients with NSCLC and 10 individuals with nonmalignant thoracic disease, we measured EGFR levels in serum using an enzyme immunoassay, and EGFR mRNA levels in lymph node and NSCLC tissues by quantitative real-time-polymerase chain reaction. We examined the correlation between them and with the clinical parameters.
  
  
  RESULTS
  Serum EGFR levels substantially decreased after surgical treatment (P < 0.001). Serum EGFR levels were correlated with smoking, surgery, and pathological type after surgery (all P < 0.05). EGFR mRNA levels in lymph node and tumor tissues were correlated more closely with lymph node metastasis (P = 0.015. EGFR mRNA in tissues was higher than that of benign pulmonary diseases (P = 0.020). There was an obvious positive correlation among EGFR levels of serum and lymph node tissues (r = 0.764; P < 0.001), serum and tumor tissues (r = 0.616; P < 0.001), and lymph node and tumor tissues (r = 0.904; P < 0.001) in NSCLCs.
  
  
  CONCLUSIONS
  The data suggest that detecting EGFR levels in serum and lymph node tissues could be a simple and effective method to diagnose and assess the clinical stage in patients with NSCLC.
authors.affiliation: Department of Internal medicine, Shandong Academy of Occupational Health and Occupational Medicine Jinan, China.
authors.forename: Yinling
authors.initials: Y
authors.lastname: Zhuo
authors.affiliation: Department of Chemotherapy Oncology, Shandong Cancer Hospital Jinan, China.
authors.forename: Qisen
authors.initials: Q
authors.lastname: Guo
authors.affiliation: Department of Thoracic Surgery, Shandong Cancer Hospital Jinan, China.
authors.forename: Pingping
authors.initials: P
authors.lastname: Song
authors.affiliation: Department of Internal Medicine, Shandong Traffic Hospital Jinan, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Oncology, Affiliated Hospital of Binzhou Medical College Binzhou, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Guo
authors.affiliation: Department of Oncology, Jinxiang People's Hospital Jinxiang, China.
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Zeng
authors.affiliation: Department of Chemotherapy Oncology, Shandong Cancer Hospital Jinan, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Guan
authors.affiliation: Department of Chemotherapy Oncology, Shandong Cancer Hospital Jinan, China.
authors.forename: Xiuju
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Internal Medicine, Affiliated Hospital of Shandong Academy of Medical Sciences Jinan, China.
authors.forename: Chenqing
authors.initials: C
authors.lastname: Zhao
keywords: EGFR; enzyme-linked immunosorbent assay; lung neoplasms; polymerase chain reaction