title: Systematic review and meta-analysis of ovarian cancers: estimation of microsatellite-high frequency and characterization of mismatch repair deficient tumor histology.
abstract: OBJECTIVE
  A meta-analytic approach was used to estimate the frequency of: (a) microsatellite instability-high (MSI-H) phenotype in unselected ovarian cancers and (b) various histologic subtypes of mismatch repair (MMR)-deficient epithelial ovarian cancers.
  
  
  METHODS
  A systematic search of the Medline electronic database was conducted to identify articles published between January 1, 1966, and December 31, 2007, that examined MMR deficiency in ovarian cancers. Data were extracted on the study population, sample size, MSI-H frequency, and histology of MMR-deficient ovarian tumors.
  
  
  RESULTS
  The pooled proportion of MSI-H ovarian cancers was 0.12 [95% confidence interval (CI), 0.08-0.17] from 18 studies with 977 cases. The proportion of histologic subtypes in the pooled analysis from 15 studies with 159 cases was serous at 0.32 (95% CI, 0.20-0.44), mucinous at 0.19 (95% CI, 0.12-0.27), endometrioid at 0.29 (95% CI, 0.22-0.36), clear cell at 0.18 (95% CI, 0.09-0.28), and mixed at 0.24 (95% CI, 0.07-0.47). There was significant heterogeneity between studies.
  
  
  CONCLUSIONS
  The frequency of the MSI-H phenotype in unselected ovarian cancers approximates 12%. MMR-deficient ovarian cancers also seem to be characterized by an overrepresentation of nonserous histologic subtypes. Knowledge of histologic subtype may aid clinicians in identifying the relatively large proportion of ovarian cancers due to MMR defects; such knowledge has potential implications for medical management.
authors.affiliation: H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida 33612, USA. tuya.pal@moffitt.org
authors.forename: Tuya
authors.initials: T
authors.lastname: Pal
authors.forename: Jenny
authors.initials: J
authors.lastname: Permuth-Wey
authors.forename: Ambuj
authors.initials: A
authors.lastname: Kumar
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Sellers
mesh_terms: D053843:DNA Mismatch Repair; D005260:Female; D006801:Humans; D053842:Microsatellite Instability; D010051:Ovarian Neoplasms / Q000235:genetics* / Q000473:pathology; D010641:Phenotype