title: The impact of IGF-1R expression on the outcomes of patients with breast cancer: a meta-analysis.
abstract: OBJECTIVE
  The value of insulin-like growth factor 1 receptor (IGF-1R) for predicting survival of patients with breast cancer remains controversial. The purpose of this study was to perform a meta-analysis of the published data to attempt to clarify the impact of IGF-1R.
  
  
  METHODS
  Studies published between January 1, 1990 and October 1, 2014 were identified using an electronic search to aggregate the available survival results. Studies were included if they reported detecting IGF-1R expression in the primary breast cancer and analyzed patient survival data according to IGF-1R status. The principal outcome measures were hazard ratios (HRs) for survival of IGF-1R-positive patients. Combined HRs and 95% confidence intervals (CIs) were estimated using fixed- or random-effects models according to between-study heterogeneity.
  
  
  RESULTS
  Ten studies, involving 5,406 patients, satisfied our inclusion criteria. Data from five studies provided the impact of IGF-1R on overall survival (OS), three studies the impact on breast cancer-specific survival (BCSS), and seven studies the impact on disease-free survival (DFS). The results of meta-analysis showed that for DFS, membranous IGF-1R positivity was not a significant predictor. The combined HR for OS/BCSS was 0.63 (95% CI: 0.42-0.95, P=0.03), indicating that membranous IGF-1R positivity was a significant predictor of better survival. IGF-1R cytoplasmic positivity was significantly associated with longer DFS and OS/BCSS (combined HR: 0.56, 95% CI: 0.35-0.89, P=0.01; combined HR: 0.55, 95% CI: 0.35-0.85, P=0.008, respectively). The results of subgroup analysis suggested that membranous IGF-1R positivity in hormone-receptor-positive breast cancer was correlated with favorable DFS (combined HR: 0.61, 95% CI: 0.41-0.92, P=0.02) and OS/BCSS (combined HR: 0.73, 95% CI: 0.57-0.93, P=0.01). Membranous IGF-1R positivity in triple-negative breast cancer predicted worse DFS (combined HR: 1.86, 95% CI: 1.03-3.34, P=0.04). Membranous IGF-1R positivity in Her-2-positive or ER (estrogen receptor)-negative breast cancer was not found to be a significant prognostic indicator.
  
  
  CONCLUSIONS
  The results of this meta-analysis suggest that IGF-1R expression has different prognostic values for patients with breast cancers of different molecular subtypes. It was a favorable prognostic indicator in unselected breast cancers and hormone-receptor-positive cancers, but indicated poor survival in triple-negative breast cancers.
authors: Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China.
authors: Shunchao
authors: S
authors: Yan
authors: Department of Respiratory Medicine, Shenyang Chest Hospital, Shenyang, People's Republic of China.
authors: Xin
authors: X
authors: Jiao
authors: Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China.
authors: Kai
authors: K
authors: Li
authors: Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China.
authors: Wusheng
authors: W
authors: Li
authors: Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China.
authors: Huawei
authors: H
authors: Zou
keywords: IGF-1R; breast cancer; disease-free survival; hazard ratio; meta-analysis; overall survival; prognosis