title: Sequential measurements of serum matrix metalloproteinase 9 to monitor chemotherapy responses in patients with advanced non-small-cell lung cancer.
abstract: BACKGROUND
  Matrix metalloproteinase 9 (MMP-9) plays an important role in tumor invasion and metastasis, including lung cancer. However, whether variations in serum MMP-9 levels can serve as a biomarker for monitoring chemotherapy curative effect remains unclear. This study was designed to investigate the association between variations in serum MMP-9 levels and chemotherapy curative effect in patients with lung cancer.
  
  
  METHODS
  A total of 82 patients with advanced lung cancer were included. All newly diagnosed patients were treated with platinum-based doublet chemotherapy. Serial measurements of serum MMP-9 levels were performed by enzyme-linked immunosorbent assay. In this manner, we chose four time points to examine the association, including before chemotherapy, and 3 weeks after the beginning of the first, second, and fourth cycles of chemotherapy.
  
  
  RESULTS
  Compared with the serum level of MMP-9 before progressive disease, patients with progressive disease had elevated serum levels of MMP-9. Compared with the previous time point of collecting specimens, the serum levels of MMP-9 in the patients with a complete response/partial response/stable disease decreased or were maintained stable. The differences of variation in serum MMP-9 levels in patients with different chemotherapy curative effects were all statistically significant after one cycle, two cycles, and four cycles (after one cycle: P<0.001; after two cycles: P<0.001; after four cycles: P=0.01). However, patients with small-cell lung cancer did not exhibit similar test results.
  
  
  CONCLUSIONS
  The variation in serum MMP-9 levels in patients with non-small-cell lung cancer during chemotherapy was closely related to chemotherapy curative effect and could be useful to monitor chemotherapy curative effect for a small portion of patients.
authors.affiliation: Department of Cellular and Molecular Biology, Beijing Chest Hospital, Capital Medical University, Beijing, People's Republic of China; Department of Cellular and Molecular Biology, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing, People's Republic of China; Health Care Ward, The First Hospital Affiliated to Inner Mongolia Medical University, Hohhot, People's Republic of China.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Qiao
authors.affiliation: Department of Cellular and Molecular Biology, Beijing Chest Hospital, Capital Medical University, Beijing, People's Republic of China; Department of Cellular and Molecular Biology, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing, People's Republic of China.
authors.forename: Xiaoran
authors.initials: X
authors.lastname: Zhai
authors.affiliation: Department of Medical Oncology, Beijing Chest Hospital, Capital Medical University, Beijing, People's Republic of China.
authors.forename: Jinghui
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Cellular and Molecular Biology, Beijing Chest Hospital, Capital Medical University, Beijing, People's Republic of China; Department of Cellular and Molecular Biology, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing, People's Republic of China.
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Department of Medical Oncology, Beijing Chest Hospital, Capital Medical University, Beijing, People's Republic of China.
authors.forename: Xinjie
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Medical Oncology, Beijing Chest Hospital, Capital Medical University, Beijing, People's Republic of China.
authors.forename: Jialin
authors.initials: J
authors.lastname: Lv
authors.affiliation: Department of Cellular and Molecular Biology, Beijing Chest Hospital, Capital Medical University, Beijing, People's Republic of China; Department of Cellular and Molecular Biology, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: Ma
authors.affiliation: Department of Cellular and Molecular Biology, Beijing Chest Hospital, Capital Medical University, Beijing, People's Republic of China; Department of Cellular and Molecular Biology, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing, People's Republic of China.
authors.forename: Lina
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Cellular and Molecular Biology, Beijing Chest Hospital, Capital Medical University, Beijing, People's Republic of China; Department of Cellular and Molecular Biology, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing, People's Republic of China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Medical Oncology, Beijing Chest Hospital, Capital Medical University, Beijing, People's Republic of China.
authors.forename: Shucai
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Cellular and Molecular Biology, Beijing Chest Hospital, Capital Medical University, Beijing, People's Republic of China; Department of Cellular and Molecular Biology, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing, People's Republic of China.
authors.forename: Wentao
authors.initials: W
authors.lastname: Yue
keywords: chemotherapy; lung adenocarcinoma; lung squamous carcinoma; prognosis; treatment monitoring