title: Expression of calcium sensing receptor and E-cadherin correlated with survival of lung adenocarcinoma.
abstract: BACKGROUND
  It has been reported that the calcium sensing receptor (CaSR), a widely expressed G protein-coupled receptor, can stimulate cell differentiation and proliferation. However, in malignant tumors, loss of CaSR expression has been associated with tumorigenesis, metastasis, and progression. Recent studies have indicated that the CaSR could promote the expression of E-cadherin, which was considered a tumor suppressor. However, in human lung adenocarcinoma, the importance of the CaSR and E-cadherin has not been sufficiently investigated.
  
  
  METHODS
  Expression levels of CaSR and E-cadherin in paraffin sections from 117 resected lung adenocarcinoma patients were evaluated by immunohistochemistry. We analyzed the correlation between our target proteins and clinical variables. Clinical significance was analyzed by multivariate Cox regression analysis, Kaplan-Meier curve, and log-rank test.
  
  
  RESULTS
  Expression of the CaSR in lung adenocarcinoma tissue was significantly lower than in the normal sample (P = 0.003). Kendall tau-b analysis showed that, in a lung adenocarcinoma sample, the expression of CaSR positively correlated with a high level of E-cadherin (P < 0.001). Lung adenocarcinoma patients with a strong expression of CaSR (P = 0.034) or E-cadherin (P = 0.001) had longer overall survival. Multivariate Cox proportional hazards model analysis showed that the combined marker was an independent prognostic indicator of overall survival (hazard ratio = 0.440, confidence interval = 0.249-0.779, P = 0.005).
  
  
  CONCLUSIONS
  We identified the CaSR as a new prognostic biomarker in lung adenocarcinoma. These results also suggested that the CaSR may become a new therapeutic target of lung adenocarcinoma.
authors.affiliation: The Fourth Department of Medical Oncology, Harbin Medical University Cancer Hospital Harbin, China.
authors.forename: Liyuan
authors.initials: L
authors.lastname: Wen
authors.affiliation: The Fourth Department of Medical Oncology, Harbin Medical University Cancer Hospital Harbin, China.
authors.forename: Lichun
authors.initials: L
authors.lastname: Sun
authors.affiliation: Department of Pathophysiology, Harbin Medical University Harbin, China.
authors.forename: Yuhui
authors.initials: Y
authors.lastname: Xi
authors.affiliation: The Fourth Department of Medical Oncology, Harbin Medical University Cancer Hospital Harbin, China.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Chen
authors.affiliation: The Fourth Department of Medical Oncology, Harbin Medical University Cancer Hospital Harbin, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Xing
authors.affiliation: The Fourth Department of Medical Oncology, Harbin Medical University Cancer Hospital Harbin, China.
authors.forename: Weiling
authors.initials: W
authors.lastname: Sun
authors.affiliation: The Fourth Department of Medical Oncology, Harbin Medical University Cancer Hospital Harbin, China.
authors.forename: Qingwei
authors.initials: Q
authors.lastname: Meng
authors.affiliation: The Fourth Department of Medical Oncology, Harbin Medical University Cancer Hospital Harbin, China.
authors.forename: Li
authors.initials: L
authors.lastname: Cai
keywords: Calcium sensing receptor (CaSR); E-cadherin; lung adenocarcinoma; survival