Long interspersed nuclear element (LINE)-1 methylation level as a molecular marker of early gastric cancer

Abstract

Background/aims: This study was performed to examine the state of long interspersed nuclear element (LINE)-1 methylation level in gastric epithelial dysplasias (GEDs) and evaluate as a molecular marker for gastric carcinogenesis when it was compared with RUNX3 expression.

Methods: We examined 89 patients with GEDs subcategorized by the Vienna classification - 41 category 3 (low grade) and 48 category 4 (high grade/intramucosal carcinoma) lesion. All tissue samples were evaluated for RUNX3 immunohistochemical staining and the level of LINE-1 methylation.

Results: The rate of negative expression of RUNX3 in category 4 lesion was significant higher than category 3 (P<0.01). LINE-1 methylation level was statistically different between category 3 and category 4 lesion (P<0.01). Between positive and negative expression of RUNX3 in GEDs, there was a significant difference of LINE-1 methylation level (P<0.01). The area under the ROC curve (AUC) of LINE-1 methylation level for diagnosis of category 4 lesion was 0.88 (95% CI, 0.76-1.00).

Conclusions: LINE-1 methylation level was well correlated with the Vienna classification of GED and it had a close relationship with the negative expression of RUNX3 in category 4 lesion. LINE-1 methylation level could be a good candidate for a molecular marker of early gastric cancer.

Keywords: Gastric cancer; Long interspersed nuclear element (LINE); RUNX3.