title: Circulating miR-200c as a diagnostic and prognostic biomarker for gastric cancer.
abstract: BACKGROUND
  MicroRNAs are aberrantly expressed and correlate with tumourigenesis and the progression of solid tumours. The miR-200 family determines the epithelial phenotype of cancer cells and regulates invasiveness and migration. Thus, we hypothesised that the quantitative detection of the miR-200 family as epithelial-specific microRNAs in the blood could be a useful clinical biomarker for gastric cancer (GC).
  
  
  METHODS
  We initially validated the expression levels of miR-200a, 200b, 200c and 141 in GC cell lines (n = 2) and blood from healthy controls (n = 19) using real-time quantitative reverse transcription PCR (qRT-PCR). The microarray expression profiles of the miR-200 family in 160 paired samples of non-tumour gastric mucosae and GC were downloaded through ArrayExpress and analysed. MiR-200c was selected for clinical validation. The qRT-PCR prospective assessment of miR-200c was performed using 67 blood samples (52 stage I-IV GC patients and 15 controls); the area under the receiver operating characteristic curve (AUC-ROC) was estimated. The Kaplan-Meier and Breslow-Wilcoxon tests were used to assess the correlation of miR-200c with overall and progression-free survival (OS and PFS). Multivariate analyses were performed using the Cox model.
  
  
  RESULTS
  The miR-200c blood expression levels in GC patients were significantly higher than in normal controls (p = 0.018). The AUC-ROC was 0.715 (p = 0.012). The sensitivity, specificity and accuracy rates of 65.4%, 100% and 73.1%, respectively, were observed. The levels of miR-200c in the blood above the cutoff defined by the ROC curve was found in 17.6% of stage I-II GC patients, 20.6% of stage III patients and 67.7% of stage IV patients (p < 0.001). The miR-200c expression levels were not associated with clinical or pathological characteristics or recent surgical procedures. There was a correlation (p = 0.016) with the number of lymph node metastases and the increased expression levels of miR-200c in blood were significantly associated with a poor OS (median OS, 9 vs 24 months; p = 0.016) and PFS (median PFS, 4 vs 11 months; p = 0.044). Multivariate analyses confirmed that the upregulation of miR-200c in the blood was associated with OS (HR = 2.24; p = 0.028) and PFS (HR = 2.27; p = 0.028), independent of clinical covariates.
  
  
  CONCLUSIONS
  These data suggest that increased miR-200c levels are detected in the blood of gastric cancer patients. MiR-200c has the potential to be a predictor of progression and survival.
authors.affiliation: Medical Oncology Department, La Coruña University Hospital, Servicio Galego de Saúde (SERGAS), As Xubias, 84, La Coruña, PC, 15006, Spain. manuel.valladares.ayerbes@sergas.es
authors.forename: Manuel
authors.initials: M
authors.lastname: Valladares-Ayerbes
authors.forename: Margarita
authors.initials: M
authors.lastname: Reboredo
authors.forename: Vanessa
authors.initials: V
authors.lastname: Medina-Villaamil
authors.forename: Pilar
authors.initials: P
authors.lastname: Iglesias-Díaz
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Lorenzo-Patiño
authors.forename: Mar
authors.initials: M
authors.lastname: Haz
authors.forename: Isabel
authors.initials: I
authors.lastname: Santamarina
authors.forename: Moisés
authors.initials: M
authors.lastname: Blanco
authors.forename: Juan
authors.initials: J
authors.lastname: Fernández-Tajes
authors.forename: Maria
authors.initials: M
authors.lastname: Quindós
authors.forename: Alberto
authors.initials: A
authors.lastname: Carral
authors.forename: Angélica
authors.initials: A
authors.lastname: Figueroa
authors.forename: Luis Miguel
authors.initials: LM
authors.lastname: Antón-Aparicio
authors.forename: Lourdes
authors.initials: L
authors.lastname: Calvo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D014408:Biomarkers, Tumor / Q000097:blood* / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000097:blood* / Q000235:genetics; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011379:Prognosis; D012372:ROC Curve; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000097:blood* / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; C533896:MIRN200 microRNA, human; D035683:MicroRNAs