title: Association between miR-200c and the survival of patients with stage I epithelial ovarian cancer: a retrospective study of two independent tumour tissue collections.
abstract: BACKGROUND
  International Federation of Gynecology and Obstetrics stage I epithelial ovarian cancer (EOC) has a significantly better prognosis than stage III/IV EOC, with about 80% of patients surviving at 5 years (compared with about 20% of those with stage III/IV EOC). However, 20% of patients with stage I EOC relapse within 5 years. It is therefore crucial that the biological properties of stage I EOCs are further elucidated. MicroRNAs (miRNAs) have shown diagnostic and prognostic potential in stage III and IV EOCs, but the small number of patients diagnosed with stage I EOC has so far prevented an investigation of its molecular features. We profiled miRNA expression in stage I EOC tumours to assess whether there is a miRNA signature associated with overall and progression-free survival (PFS) in stage I EOC.
  
  
  METHODS
  We analysed tumour samples from 144 patients (29 of whom relapsed) with stage I EOC gathered from two independent tumour tissue collections (A and B), both with a median follow-up of 9 years. 89 samples from tumour tissue collection A were stratified into a training set (51 samples, 15 of which were from patients who relapsed) for miRNA signature generation, and into a validation set (38 samples, seven of which were from patients who relapsed) for signature validation. Tumour tissue collection B (55 samples, seven of which were from patients who relapsed) was used as an independent test set. The Cox proportional hazards model and the log-rank test were used to assess the correlation of quantitative reverse transcription PCR (qRT-PCR)-validated miRNAs with overall survival and PFS.
  
  
  RESULTS
  A signature of 34 miRNAs associated with survival was generated by microarray analysis in the training set. In both the training set and validation set, qRT-PCR analysis confirmed that 11 miRNAs (miR-214, miR-199a-3p, miR-199a-5p, miR-145, miR-200b, miR-30a, miR-30a*, miR-30d, miR-200c, miR-20a, and miR-143) were expressed differently in relapsers compared with non-relapsers. Three of these miRNAs (miR-200c, miR-199a-3p, miR-199a-5p) were associated with PFS, overall survival, or both in multivariate analysis. qRT-PCR analysis in the test set confirmed the downregulation of miR-200c in relapsers compared with non-relapsers, but not the upregulation of miR-199a-3p and miR-199a-5p. Multivariate analysis confirmed that downregulation of miR-200c in the test set was associated with overall survival (HR 0·094, 95% CI 0·012-0·766, p=0·0272) and PFS (0·035, 0·004-0·311; p=0·0026), independent of clinical covariates.
  
  
  CONCLUSIONS
  miR-200c has potential as a predictor of survival, and is a biomarker of relapse, in stage I EOC.
  
  
  BACKGROUND
  Nerina and Mario Mattioli Foundation, Cariplo Foundation (Grant Number 2010-0744), and the Italian Association for Cancer Research.
authors.affiliation: Department of Oncology, Mario Negri Institute for Pharmacological Research, Milan, Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Marchini
authors.forename: Duccio
authors.initials: D
authors.lastname: Cavalieri
authors.forename: Robert
authors.initials: R
authors.lastname: Fruscio
authors.forename: Enrica
authors.initials: E
authors.lastname: Calura
authors.forename: Daniela
authors.initials: D
authors.lastname: Garavaglia
authors.forename: Ilaria
authors.initials: I
authors.lastname: Fuso Nerini
authors.forename: Costantino
authors.initials: C
authors.lastname: Mangioni
authors.forename: Giorgio
authors.initials: G
authors.lastname: Cattoretti
authors.forename: Luca
authors.initials: L
authors.lastname: Clivio
authors.forename: Luca
authors.initials: L
authors.lastname: Beltrame
authors.forename: Dionyssios
authors.initials: D
authors.lastname: Katsaros
authors.forename: Luca
authors.initials: L
authors.lastname: Scarampi
authors.forename: Guido
authors.initials: G
authors.lastname: Menato
authors.forename: Patrizia
authors.initials: P
authors.lastname: Perego
authors.forename: Giovanna
authors.initials: G
authors.lastname: Chiorino
authors.forename: Alessandro
authors.initials: A
authors.lastname: Buda
authors.forename: Chiara
authors.initials: C
authors.lastname: Romualdi
authors.forename: Maurizio
authors.initials: M
authors.lastname: D'Incalci
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor; D000077216:Carcinoma, Ovarian Epithelial; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D035683:MicroRNAs; D008875:Middle Aged; D009375:Neoplasms, Glandular and Epithelial / Q000235:genetics / Q000401:mortality / Q000473:pathology; D010051:Ovarian Neoplasms / Q000235:genetics / Q000401:mortality / Q000473:pathology; D011379:Prognosis; D012189:Retrospective Studies
chemical_list: D014408:Biomarkers, Tumor; C533896:MIRN200 microRNA, human; D035683:MicroRNAs