Danai TiwawechRatakorn SrisutteePrakasit RattanatanyongCharoenchai PuttipanyalearsNakarin KitkumthornApiwat MutiranguraChulalongkorn UniversityMahidol University2018-11-092018-11-092014-01-01Asian Pacific Journal of Cancer Prevention. Vol.15, No.22 (2014), 9797-9800151373682-s2.0-84921519173https://repository.li.mahidol.ac.th/handle/20.500.14594/33436Background: Nasopharyngeal carcinoma (NPC) is a common cancer in Southern China and Southeast Asia. Alu elements are among the most prevalent repetitive sequences and constitute 11% of the human genome. Although Alu methylation has been evaluated in many types of cancer, few studies have examined the levels of this modification in serum from NPC patients. Objective: To compare the Alu methylation levels and patterns between serum from NPC patients and normal controls. Materials and Methods: Sera from 50 NPC patients and 140 controls were examined. Quantitative combined bisulfite restriction analysis-Alu (qCOBRA-Alu) was applied to measure Alu methylation levels and characterize Alu methylation patterns. Amplified products were classified into four patterns according to the methylation status of 2 CpG sites: hypermethylated (methylation at both loci), partially methylated (methylation of either of the two loci), and hypomethylated (unmethylated at both loci). Results: A comparison of normal control sera with NPC sera revealed that the latter presented a significantly lower methylation level (p = 0.0002) and a significantly higher percentage of hypomethylated loci (p = 0.0002). The sensitivity of the higher percentage of Alu hypomethyted loci for distinguishing NPC patients from normal controls was 96%. Conclusions: Alu elements in the circulating DNA of NPC patients are hypomethylated. Moreover, Alu hypomethylated loci may represent a potential biomarker for NPC screening.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyMedicineArticleSCOPUS10.7314/APJCP.2014.15.22.9797