Anand R, Prakash S S, Veeramanikandan R, Kirubakaran Richard
Department of Biochemistry, Christian Medical College, Vellore, 632002, Tamilnadu, India,
J Cancer Res Clin Oncol. 2014 Jul;140(7):1075-85. doi: 10.1007/s00432-014-1634-2. Epub 2014 Apr 5.
Apolipoprotein E (ApoE), a protein primarily involved in lipoprotein metabolism, occurs in three isoforms (E2, E3 and E4). Studies evaluating the association between APOE genotype and incidence of malignancies have given inconclusive results.
The objective of the present study was to analyze the association between APOE genotype and incidence of cancer by a meta-analysis.
We conducted a literature search in the electronic databases for studies with information on APOE genotype in malignancies. Sixteen studies (14 case-control and 2 cohort; 77,970 controls and 12,010 cases) were included for the present meta-analysis. Pooled odds ratios (OR) with 95 % confidence intervals (CI) were calculated assuming a random-effect model for all the genotypes and alleles. Subgroup analyses based on study design, ethnicity of populations, site of cancer and source of controls were performed as a post hoc measure. Appropriate tests to detect heterogeneity, publication bias and sensitivity were done at all stages. The review protocol is registered with the PROSPERO database vide registration number CRD42013006496.
The pooled effect measure for the comparisons did not reveal an association in primary analyses. In the subgroup analyses, we observed a negative association between APOE4+ genotypes and overall risk of cancer in the cohort study subgroup (pooled OR 0.86; 95 % CI 0.82-0.91; p < 0.00001; I (2) = 0 %). Sensitivity analyses did not alter the overall pooled effect measure, and there were no evidences to suggest a publication bias.
Overall, the present meta-analysis did not show any association between APOE alleles and genotypes with incidence of cancer in general.
载脂蛋白E（ApoE）是一种主要参与脂蛋白代谢的蛋白质，有三种异构体（E2、E3和E4）。评估APOE基因型与恶性肿瘤发病率之间关联的研究结果尚无定论。
本研究旨在通过荟萃分析来分析APOE基因型与癌症发病率之间的关联。
我们在电子数据库中进行文献检索，以查找有关恶性肿瘤中APOE基因型信息的研究。本荟萃分析纳入了16项研究（14项病例对照研究和2项队列研究；77970名对照和12010例病例）。针对所有基因型和等位基因，采用随机效应模型计算合并优势比（OR）及95%置信区间（CI）。作为事后分析措施，基于研究设计、人群种族、癌症部位和对照来源进行亚组分析。在各个阶段都进行了检测异质性、发表偏倚和敏感性的适当检验。该综述方案已在PROSPERO数据库注册，注册号为CRD42013006496。
在初步分析中，比较的合并效应量未显示出关联。在亚组分析中，我们观察到在队列研究亚组中，APOE4 +基因型与总体癌症风险之间存在负相关（合并OR 0.86；95%CI 0.82 - 0.91；p < 0.00001；I² = 0%）。敏感性分析未改变总体合并效应量，且没有证据表明存在发表偏倚。
总体而言，本荟萃分析未显示APOE等位基因和基因型与一般癌症发病率之间存在任何关联。
