ABSTRACT: BACKGROUND AND OBJECTIVE:Insulin-like growth factor 1 (IGF1) gene three prime untranslated region (3'-UTR) polymorphisms have been reported to be associated with cancer risk. However, the conclusions of the relevant studies are not consistent. The present meta-analysis evaluates the relationship between IGF1 gene 3'-UTR polymorphisms (rs5742714, rs6214, and rs6220) and cancer risk. METHODS:Articles regarding the relationship between IGF1 rs5742714, rs6214, and rs6220 polymorphisms and cancer risk were selected by searching the PubMed, Embase, and Web of Science databases before April 30, 2018. Altogether, we obtained 34 case-controlled studies from 20 articles, including 21,568 cases and 31,199 controls. The strength of associations was quantified using odds ratios (ORs) and the corresponding 95% confidence intervals (CIs). RESULTS:In the present meta-analysis, no significant associations were detected between rs5742714, rs6214, and rs6220 and overall cancer risk. Thus, in stratified analyses, we found that rs6214 was associated with a significantly reduced risk of breast cancer under the allele, heterozygote, and dominant models (A vs G: OR, 0.94, 95% CI,0.88-1.00, P?=?.044; GA vs GG: OR, 0.88, 95% CI, 0.80-0.97, P?=?.012; AA?+?GA vs GG: OR, 0.89, 95% CI, 0.81-0.97, P?=?.011), as well as pancreatic cancer under the recessive model (AA vs GA?+?GG: OR, 0.68, 95% CI,0.53-0.87, P?=?.003). Also, rs6220 was associated with a significantly increased risk of breast cancer under the homozygote model (GG vs AA: OR, 1.23, 95% CI, 1.02-1.48, P?=?.031). In addition, rs6220 was found to increase overall cancer risk among Caucasians under the allele model (G vs A: OR, 1.06, 95% CI, 1.00-1.13, P?=?.043). CONCLUSIONS:In this meta-analysis, we investigated and reviewed the relationship between IGF1 gene 3'-UTR polymorphisms (rs5742714, rs6214, and rs6220) and cancer risk based on present epidemiological studies. Further studies are needed to draw more precise conclusions in the future.
