Clinical implications of microsomal prostaglandin e synthase-1 overexpression in human non-small-cell lung cancer
Hao-Wei Wang1, Chung-Tsen Hsueh, Chien-Fu Jeff Lin
1Division of Thoracic Surgery, Department of Surgery, Taipei Veterans General Hospital and School of Medicine, National Yang-Ming University, 201, Sec 2, Shih-Pai Road, Taipei 112, Taiwan.
Background:
Microsomal prostaglandin E synthase-1 (mPGES-1) has recently been found to overexpress in human cancers, including non-small-cell lung cancer (NSCLC). However, the clinical value is largely unknown. The aim of this study was to investigate the associations between mPGES-1 expression in NSCLC and the clinical characteristics and survival outcome.
Methods:
Between 2001 and 2003, paired fresh tumorous and nontumorous samples were prospectively procured from patients undergoing surgery for NSCLC. The expression of mPGES-1 was assessed by using Western blot in 93 subjects and reverse transcriptase-polymerase chain reaction in 35. Overexpression of mPGES-1 was defined as a more than 2-fold expression in the tumorous sample compared with the corresponding nontumorous one. Immunohistochemistry was used to confirm its localization to the tumor cells. In a subset of 30 cases, cyclooxygenase-2 (COX-2) was also analyzed to assess its association with mPGES-1.
Results:
The protein and messenger RNA of mPGES-1 were both expressed at higher levels in the tumor samples (P < .001 and P = .006, respectively). The expressions of mPGES-1 and COX-2 were unrelated (P = .715). Overexpression of mPGES-1 protein was observed in 61 (65.6%) of 93 patients, but it was not significantly associated with the clinicopathologic characteristics or overall and disease-free survivals. However, mPGES-1 overexpression seemed to be associated with the likelihood of subsequent pulmonary metastases and a lower tendency for developing bony metastases (P = .001 and P = .006, respectively).
Conclusions:
Our results demonstrated that mPGES-1 was overexpressed in NSCLC, unassociated with COX-2. Overexpression of mPGES-1 per se was not a prognostic indicator, but it might be implicated in the organ preference of metastasis.
