title: Association between the expression of four upregulated miRNAs and extrathyroidal invasion in papillary thyroid carcinoma.
abstract: BACKGROUND
  MicroRNAs (miRNAs) are important diagnostic and prognostic markers in cancer. In the study reported here, we analyzed the potential relationship between miRNA expression and extrathyroidal invasion in papillary thyroid carcinoma (PTC).
  
  
  METHODS
  Samples from 91 patients with PTC were collected from January 2008 to April 2012 at our hospital. To detect the levels of miRNA expression in fresh frozen tissues from patients with extrathyroidal invasion (n = 3) and non-extrathyroidal invasion (n = 3), miRNA array was carried out. The upregulated miRNAs between the two groups were confirmed by using real-time reverse transcriptase polymerase chain reaction.
  
  
  RESULTS
  The levels of miR-146b, miR-221, miR-222, and miR-135b were significantly higher in the extrathyroidal invasion group than in the non-extrathyroidal invasion group (P = 0.001, 0.019, 0.004, and 0.006, respectively). In addition, the miR-146b expression level was significantly higher in the massive extrathyroidal invasion group than in the minimal extrathyroidal invasion group (P = 0.016). The expression levels of miR-146b, miR-222, and miR-135b were significantly associated with tumor size (P = 0.018, 0.008, and 0.024, respectively). The upregulation of miR-146b and miR-222 was significantly associated with higher tumor-node-metastasis stage (P = 0.004 and 0.0001, respectively). The expression level of miR-222 was also correlated with age and sex (P = 0.048 and 0.002, respectively).
  
  
  CONCLUSIONS
  Our results reveal that the expression of four miRNAs correlated with extrathyroidal invasion and other clinicopathologic features in PTCs, which may support their potential clinical value as prognostic biomarkers for PTCs.
authors.affiliation: Department of General Surgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, People's Republic of China.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Wang
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Liang
authors.initials: L
authors.lastname: He
authors.forename: Wenwu
authors.initials: W
authors.lastname: Dong
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Zhongyan
authors.initials: Z
authors.lastname: Shan
authors.forename: Weiping
authors.initials: W
authors.lastname: Teng
keywords: PTC; miR-135b; miR-146b; miR-221; miR-222