The Central Laboratory of Nanjing First Hospital, Nanjing Medical University, Nanjing, 210006 Jiangsu Province, China.
Gene. 2013 Aug 1;525(1):92-8. doi: 10.1016/j.gene.2013.04.041. Epub 2013 Apr 28.
Insulin-like growth factor (IGF)-I has been implicated in processes leading to breast cancer initiation and progression. A CA repeat polymorphism in the promoter region of IGF-I may suppress transcriptional activity and be associated with risk of breast cancer. A variety of case-control studies have been published evaluating the association between IGF1 CA repeat polymorphism and breast cancer. However, those published studies yielded contradictory conclusions.
This meta-analysis enrolled eleven studies to estimate the overall breast cancer risk of IGF1 CA repeat polymorphism. There was no significantly breast cancer risk found for pooled ORs among all the models. In the sub-stratified analysis by ethnicity, significantly decreased risks were found among Caucasian (19/19 versus non19/non19: OR=0.81, 95% CI: 0.70-0.94, P=0.922; 19/non19 versus non19/non19: OR=0.86, 95% CI: 0.74-0.99, P=0.005; dominant model: OR=0.84, 95% CI: 0.73-0.96, P=0.871). However, no significantly breast cancer risk was found among Asian and other ethnicities for all the genetic models. Furthermore, in the menopausal status stratified analysis, a significant decreased risk for postmenopausal woman was observed in the comparison of genotype 19/19 versus 19/non19+non19/non19: OR=0.89, 95% CI: 0.81-0.99, P=0.603. In addition, in the stratified analysis by case size, significantly decreased risk was observed in studies whose case size was more than 500 (19/19 versus 19/non19+non19/non19: OR=0.92, 95% CI: 0.86-1.00, P=0.457).
This study suggested that genotype 19/19 of IGF1 CA repeat polymorphism is a decreased risk for developing breast cancer in Caucasian but not in Asian, indicating that the association might be adjusted by race.
胰岛素样生长因子（IGF）-I 已被牵连到导致乳腺癌发生和发展的过程中。IGF-I 启动子区域的 CA 重复多态性可能会抑制转录活性，并与乳腺癌风险相关。已经发表了许多评估 IGF1 CA 重复多态性与乳腺癌之间关联的病例对照研究。然而，这些已发表的研究得出了相互矛盾的结论。
这项荟萃分析纳入了 11 项研究，以评估 IGF1 CA 重复多态性与总体乳腺癌风险的关系。在所有模型中，未发现 CA 重复多态性与乳腺癌风险之间存在显著关联。按种族进行亚组分析时，在白种人群中发现风险显著降低（19/19 与非 19/非 19：OR=0.81，95%CI：0.70-0.94，P=0.922；19/非 19 与非 19/非 19：OR=0.86，95%CI：0.74-0.99，P=0.005；显性模型：OR=0.84，95%CI：0.73-0.96，P=0.871）。然而，在所有遗传模型中，未发现亚洲人和其他种族的乳腺癌风险显著降低。此外，在绝经状态分层分析中，与基因型 19/19 相比，绝经后女性的风险显著降低 19/非 19+非 19/非 19：OR=0.89，95%CI：0.81-0.99，P=0.603。此外，在病例大小分层分析中，在病例大小超过 500 的研究中观察到风险显著降低（19/19 与 19/非 19+非 19/非 19：OR=0.92，95%CI：0.86-1.00，P=0.457）。
本研究表明，IGF1 CA 重复多态性的基因型 19/19 是白种人患乳腺癌的风险降低，但不是亚洲人，表明这种关联可能受种族影响。
