title: The Prognostic Value of Decreased LKB1 in Solid Tumors: A Meta-Analysis.
abstract: BACKGROUND
  Liver kinase B1 (LKB1) is a protein kinase that regulates the growth, integrity and polarity of mammalian cells. Recent studies have reported the prognostic value of decreased LKB1 expression in different tumors. However, the results of these studies remain controversial. Therefore, this meta-analysis was performed to more accurately estimate the role of decreased LKB1 in the prognostication of human solid tumors.
  
  
  METHODS
  A systematic literature search in the electronic databases PubMed, Embase, Web of Science and CNKI (updated to October 15, 2015) was performed to identify eligible studies. The overall survival (OS), relapse-free survival (RFS), disease-free survival (DFS) and clinicopathological features data were collected from these studies. The hazard ratios (HRs), odds ratios (ORs) and 95% confidence intervals (CIs) were calculated and pooled with a random-effects models using Stata12.0 software.
  
  
  RESULTS
  A total of 14 studies covering 1915 patients with solid tumors were included in this meta-analysis. Decreased LKB1 was associated with poorer OS in both the univariate (HR: 1.86, 95%CI: 1.42-2.42, P<0.001) and multivariate (HR: 1.55, 95%CI: 1.09-2.21, P = 0.015) analyses. A subgroup analysis revealed that the associations between decreased LKB1 and poor OS were significant within the Asian region (HR 2.18, 95%CI: 1.66-2.86, P<0.001) and obvious for lung cancer (HR: 2.16, 95%CI: 1.47-3.18, P<0.001). However, the articles that involved analyses of both RFS and DFS numbered only 3, and no statistically significant correlations of decreased LKB1 with RFS or DFS were observed in this study. Additionally, the pooled odds ratios (ORs) indicated that decreased LKB1 was associated with larger tumor size (OR: 1.60, 95%CI: 1.09-2.36, P = 0.017), lymph node metastasis (OR: 2.41, 95%CI: 1.53-3.78, P<0.001) and a higher TNM stage (OR: 3.35, 95%CI: 2.20-5.09, P<0.001).
  
  
  CONCLUSIONS
  These results suggest that decreased LKB1 expression in patients with solid tumors might be related to poor prognosis and serve as a potential predictive marker of poor clinicopathological prognostic factors. Additional studies are required to verify the clinical utility of decreased LKB1 in solid tumors.
authors.affiliation: Department of Geriatrics, Respiratory Medicine, Xiangya Hospital of Central South University, Changsha, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Xiao
authors.affiliation: Department of Geriatrics, Respiratory Medicine, Xiangya Hospital of Central South University, Changsha, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zou
authors.affiliation: Department of Respiratory Medicine, Xiangya Hospital of Central South University, Changsha, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Geriatrics, Respiratory Medicine, Xiangya Hospital of Central South University, Changsha, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Geriatrics, Respiratory Medicine, Xiangya Hospital of Central South University, Changsha, China.
authors.forename: Mingxuan
authors.initials: M
authors.lastname: Xie
authors.affiliation: Department of Geriatrics, Respiratory Medicine, Xiangya Hospital of Central South University, Changsha, China.
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Lu
authors.affiliation: Department of Geriatrics, Respiratory Medicine, Xiangya Hospital of Central South University, Changsha, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Geriatrics, Respiratory Medicine, Xiangya Hospital of Central South University, Changsha, China.
authors.forename: Bixiu
authors.initials: B
authors.lastname: He
authors.affiliation: Department of Biochemistry and Biology, University of South China, Hengyang, China.
authors.forename: Shuya
authors.initials: S
authors.lastname: He
authors.affiliation: Laboratory of Cancer Experimental Therapy, Atlanta Research & Educational Foundation (151F), Atlanta VA Medical Center, Decatur, GA, United States of America.
authors.forename: Shaojin
authors.initials: S
authors.lastname: You
authors.affiliation: Department of Geriatrics, Respiratory Medicine, Xiangya Hospital of Central South University, Changsha, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Chen
mesh_terms: D000091162:AMP-Activated Protein Kinase Kinases; D006801:Humans; D009369:Neoplasms / Q000378:metabolism*; D011379:Prognosis; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*
chemical_list: D017346:Protein Serine-Threonine Kinases; C109790:STK11 protein, human; D000091162:AMP-Activated Protein Kinase Kinases