title: Association between sodium iodide symporter and differentiated Thyroid cancer: a meta-analysis of 9 studies.
abstract: BACKGROUND
  As many studies proved that sodium iodide symporter (NIS) plays a key role in radioactive iodide (RAI) therapy of thyroid cancer, however, a growing number of studies suggests that part of differentiated thyroid carcinomas (DTC) with overexpression of NIS are insensitive to RAI well.
  
  
  OBJECTIVE
  The aim of this meta-analysis is to assess the expression of NIS in differentiated thyroid cancer, compared with normal thyroid tissue.
  
  
  METHODS
  PUBMED, Sinomed, CNKI, Wanfang and VIP were searched for relevant case-control studies up to now.
  
  
  METHODS
  Studies that concerning the qualitative expression NIS in DTC were included.
  
  
  METHODS
  Working independently, authors used a standard form to extract data. For quality assessment, Newcastle-Ottawa Scale (NOS) were applied.
  
  
  RESULTS
  Totally nine eligible studies included, involving 765 cases and 473 controls. The results revealed that the expression of NIS had a statistically increased in DTC, compared with controls (OddsRadio OR: 1.47, 95% CI: 1.12 to 1.94, Z=2.78, P=0.005). Since the existence of the significant heterogeneity, subgroup analysis and sensitivity analysis were performed and found that the heterogeneity came from the different criteria evaluate positive NIS expression (Liu 2008, Mu 2010) and the small simple size of the control group (Lin. J D2001). The heterogeneity disappeared or dropped to below 50% after remove these studies.
  
  
  CONCLUSIONS
  Our study shows that the expression of NIS is significantly increased in DTC, which could help explain the reason for individual with a poor response to RAI therapy. In other word, the reduced iodide uptake in thyroid cancer may not caused by the decreased expression of NIS, function of NIS protein or its post-transcriptional translocation might be the point.
authors.affiliation: Department of Internal Medicine, Division of Endocrinology, Shandong Provincial Qian Foshan Hospital Jinan 250014, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Department of Internal Medicine, Division of Endocrinology, Shandong Provincial Qian Foshan Hospital Jinan 250014, China.
authors.forename: Huanjun
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Internal Medicine, Division of Endocrinology, Shandong Provincial Qian Foshan Hospital Jinan 250014, China.
authors.forename: Junyu
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Internal Medicine, Division of Endocrinology, Shandong Provincial Qian Foshan Hospital Jinan 250014, China.
authors.forename: Jinming
authors.initials: J
authors.lastname: Yao
authors.affiliation: Department of Internal Medicine, Division of Endocrinology, Shandong Provincial Qian Foshan Hospital Jinan 250014, China.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Shang
authors.affiliation: Department of Internal Medicine, Division of Endocrinology, Qilu Hospital of Shandong University Jinan 250012, China.
authors.forename: Huangao
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Department of Internal Medicine, Division of Endocrinology, Shandong Provincial Qian Foshan Hospital Jinan 250014, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Liao
authors.affiliation: Department of Internal Medicine, Division of Endocrinology, Qilu Hospital of Shandong University Jinan 250012, China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Dong
keywords: Differentiated thyroid cancer; meta-analysis; sodium iodide symporter