title: Inverse association between cyclooxygenase-2 overexpression and microsatellite instability in gastric cancer.
abstract: This study examined the association between cyclooxygenase-2 (COX-2) overexpression and microsatellite instability (MSI) in gastric cancer. COX-2 expression was assessed by immunohistochemistry and scored in a semi-quantitative manner whereas MSI status was characterized by nine microsatellite markers. The clinicopathological features of cancers including survival data were analyzed. Of the 109 gastric cancers studied, COX-2 overexpression and high level of MSI (MSI-H) was detected in 64.2 and 22.0% cases respectively. Gastric tumors with MSI-H phenotypes had significantly lower level of COX-2 expression levels when compared to MSI-L and MSS tumors (P=0.002). Moreover, COX-2 overexpression was associated with tumor invasion beyond submucosa (P=0.045) and there was a trend favoring better survival in gastric cancers without COX-2 overexpression (P=0.07). The results from this study suggest that gastric cancer with microsatellite instability or COX-2 overexpression present with diverse clinicopathological features.
authors.affiliation: Department of Anatomical & Cellular Pathology, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong.
authors.forename: T L
authors.initials: TL
authors.lastname: Lee
authors.forename: W K
authors.initials: WK
authors.lastname: Leung
authors.forename: J Y
authors.initials: JY
authors.lastname: Lau
authors.forename: J H
authors.initials: JH
authors.lastname: Tong
authors.forename: E K
authors.initials: EK
authors.lastname: Ng
authors.forename: F K
authors.initials: FK
authors.lastname: Chan
authors.forename: S C
authors.initials: SC
authors.lastname: Chung
authors.forename: J J
authors.initials: JJ
authors.lastname: Sung
authors.forename: K F
authors.initials: KF
authors.lastname: To
mesh_terms: D015331:Cohort Studies; D051546:Cyclooxygenase 2; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis*; D008297:Male; D008565:Membrane Proteins; D018895:Microsatellite Repeats / Q000235:genetics*; D008875:Middle Aged; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D013274:Stomach Neoplasms / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D015996:Survival Rate
chemical_list: D007527:Isoenzymes; D008565:Membrane Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases