title: Alterations in the LINE-1 methylation pattern in patients with lichen simplex chronicus.
abstract: BACKGROUND
  Long interspersed element-1 (LINE-1) and short interspersed element (Alu) retrotransposons have been identified to influence the human genome by modifications in gene expression. Variations in LINE-1 and Alu methylation have been shown to be associated with many diseases, predominantly malignancies and autoimmune diseases. Moreover, the degree and pattern of LINE-1 methylation are related to risk, prognosis and aggressiveness of several cancers. However, a similar study has not been performed in lichen simplex chronicus (LSC).
  
  
  OBJECTIVE
  To evaluate DNA methylation status of repetitive sequences in LSC.
  
  
  RESULTS
  The %mCmC of LINE-1 was significantly decreased in keratinocytes from patients with LSC (p=0.012). Moreover, the %mCuC was significantly lower in LSC than controls (p=0.029). Conversely, %uCmC was significantly higher LSC than controls (p=0.004). A receiver-operating characteristic (ROC) curve analysis demonstrated that % mCmC, % mCuC and % uCmC were highly sensitive and specific for LSC with an optimal cut-off value. There were no significant differences in Alu methylation in keratinocytes from LSC patients.
  
  
  METHODS
  We determined the level and pattern of LINE-1 and Alu methylation in keratinocytes from patients with LSC (n=10) compared to normal controls (n=13), by the improved combined bisulfite restriction analysis of LINE-1 and Alu (COBRA-LINE-1 and Alu). COBRA-LINE-1 classifies LINE-1 loci according to the methylation patterns of two CpG dinucleotides in the 5'UTR into four categories: hypermethylated (mCmC), hypomethylated (uCuC), and two forms of partially methylated loci (uCmC and mCuC).
  
  
  CONCLUSIONS
  Changes in the LINE-1 pattern were revealed in the epidermis from patients with LSC. A particular LINE-1 methylation pattern is indicative of LSC and might be used as a diagnostic tool.
authors.affiliation: Graduate School Chulalongkorn University, Bangkok, Thailand.
authors.forename: Surasak
authors.initials: S
authors.lastname: Yooyongsatit
authors.forename: Kriangsak
authors.initials: K
authors.lastname: Ruchusatsawat
authors.forename: Pakpoom
authors.initials: P
authors.lastname: Supiyaphun
authors.forename: Nopadon
authors.initials: N
authors.lastname: Noppakun
authors.forename: Apiwat
authors.initials: A
authors.lastname: Mutirangura
authors.forename: Jongkonnee
authors.initials: J
authors.lastname: Wongpiyabovorn
mesh_terms: D000328:Adult; D000368:Aged; D018899:CpG Islands; D019175:DNA Methylation; D057890:Epigenomics; D005260:Female; D005819:Genetic Markers; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism; D020084:Long Interspersed Nucleotide Elements / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009450:Neurodermatitis / Q000235:genetics*
chemical_list: D005819:Genetic Markers