Circulating soluble advanced glycation end product is inversely associated with the significant risk of developing cancer: evidence from a meta-analysis

Currently, advanced glycation end product (RAGE) is receiving much attention in carcinogenesis research due to its involvement in cancer progression and metastasis. We therefore sought to examine the association of circulating soluble RAGE (sRAGE) with all types of cancer by a meta-analysis. The PubMed and EMBASE databases were searched before March 1, 2014. Data and study quality were assessed in duplicate. Effect estimates were expressed as weighted mean difference (WMD) and its 95 % confidence interval (CI). Altogether, nine eligible articles including 1,337 cancer patients and 1,839 controls were analyzed. The overall analysis indicated that circulating sRAGE was remarkably reduced by 222.07 pg/ml in cancer patients compared with controls (95 % CI: -373.77 to -70.37; P = 0.004), with heterogeneity and without publication bias. In subgroup analyses, this reduction was weakened yet still significant in prospective studies (WMD = -87.62; 95 % CI: -138.60 to -36.63; P = 0.001) with improved heterogeneity (I (2) = 56.5 %; P = 0.056). Restricting analyses to the large studies (total number of subjects a parts per thousand yen200) identified significant reduction of circulating sRAGE in cancer patients relative to controls (WMD = -231.34; 95 % CI: -450.10 to -12.58; P = 0.038). Further meta-regression analysis showed that smoking status explained some part of heterogeneity for the association of circulating sRAGE with cancer risk (regression coefficient: -67.02; P = 0.046). Our findings demonstrate a protective role of circulating sRAGE in the development of cancer, especially in patients without diabetes mellitus or with normal renal function.