LINE-1 hypomethylation level in patients with soft tissue tumor

Abstract

Background : LINE-1 is a non-long terminal retrotransposon, comprising 17% in human genome. The aberrant methylation of LINE-1 can cause mitotic recombination and genomic instability leading to soft tissue tumor. However, the study of LINE-1 methylation in soft tissue tumor has received little attention.

Objectives : To determine LINE-1 methylation level in neoplastic tissues compared with non-neoplastic adjacent tissues of soft tissue tumor patients and to investigate the correlation of LINE-1 methylation between neoplastic
tissues and peripheral blood leukocytes.

Methods : Thirty-five patients with soft tissue tumor and 107 healthy controls were recruited. LINE-1 methylation level was analyzed by using quantitative combined bisulfite restriction analysis.

Results : LINE-1 methylation level was statistically significantly lower ( = 0.036) in neoplastic tissues than in non-neoplastic adjacent tissues but there was no significant difference in LINE-1 methylation among benign tumor,
malignant tumor, and non-neoplastic adjacent tissues. In addition, LINE-1 methylation was not different in each subgroup of soft tissue tumor. Nevertheless, there was a positive correlation of LINE-1 methylation level
between neoplastic tissues and peripheral blood leukocytes (r = 0.812,  < 0.001).

Conclusion : These findings suggest that there was LINE-1 hypomethylation in soft tissue tumor. Thus, LINE-1 hypomethylation might play a crucial role in the pathogenesis of soft tissue tumor.