摘要Background: DNA hypomethylation of long interspersed nuclear elements-1 (LINEs-1) occurs during carcinogenesis, whereas information addressing LINE-1 methylation in Wilms tumor (WT) is limited.The main purpose of our study was to quantify LINE-1 methylation levels and evaluate their relationship with relative telomere length (TL) in WT.Methods: We investigated LINE-1 methylation and relative TL using bisulfite-polymerase chain reaction (PCR) pyrosequencing and quantitative PCR, respectively, in 20 WT tissues, 10 normal kidney tissues and a WT cell line.Significant changes were analyzed by t-tests.Results: LINE-1 methylation levels were significantly lower (P ＜ 0.05) and relative TLs were significantly shorter (P ＜ 0.05) in WT compared with normal kidney.There was a significant positive relationship between LINE-1 methylation and relative TL in WT (r =0.671,P =0.001).LINE-1 Methylation levels were significantly associated with global DNA methylation (r =0.332, P ＜ 0.01).In addition, relative TL was shortened and LINE-1 methylation was decreased in a WT cell line treated with the hypomethylating agent 5-aza-2'-deoxycytidine compared with untreated WT cell line.Conclusion: These results suggest that LINE-1 hypomethylation is common and may be linked to telomere shortening in WT.