Decreased LINE-1 methylation levels in aldosterone-producing adenoma

Purpose: Abnormal global DNA methylation levels are associated with many diseases. In this study, we examined long interspersed nuclear elements-1 (LINE-1) methylation as a biomarker for abnormal global DNA methylation and aldosterone-producing adenoma (APA). Methods: Tissues from 25 APA and 6 normal adrenal glands (NAs) were analyzed for LINE-1 methylation by real-time methylation-specific polymerase chain reaction. The estimated LINE-1 methylation level was then tested for correlation with the clinicopathologic parameters of APA patients. Results: The methylation index (MI) level for LINE-1 was 0.91 in NA samples and 0.77 in APA samples (P < 0.001). For the APA samples, there were no statistical correlations between the MI level and various clinicopathologic parameters such as gender (P = 0.07). Conclusion: LINE-1 methylation is significantly lower in APA samples than in NA samples. LINE-1 methylation is not correlated with the clinical characteristics of APA.