title: The Human Long Interspersed Element-1 Retrotransposon: An Emerging Biomarker of Neoplasia.
abstract: A large portion of intronic and intergenic space in our genome consists of repeated sequences. One of the most prevalent is the long interspersed element-1 (LINE-1, L1) mobile DNA. LINE-1 is rightly receiving increasing interest as a cancer biomarker.
  
  
  
  Intact LINE-1 elements are self-propagating. They code for RNA and proteins that function to make more copies of the genomic element. Our current understanding is that this process is repressed in most normal cells, but that LINE-1 expression is a hallmark of many types of malignancy. Here, we will consider features of cancer cells when cellular defense mechanisms repressing LINE-1 go awry. We will review evidence that genomic LINE-1 methylation, LINE-1-encoded RNAs, and LINE-1 ORF1p (open reading frame 1 protein) may be useful in cancer diagnosis.
  
  
  
  The repetitive and variable nature of LINE-1 DNA sequences poses unique challenges to studying them, but recent advances in reagents and next generation sequencing present opportunities to characterize LINE-1 expression and activity in cancers and to identify clinical applications.
authors.affiliation: McKusick-Nathans Institute of Genetic Medicine (IGM) and.|Medical Scientist Training Program (MSTP), Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Daniel
authors.initials: D
authors.lastname: Ardeljan
authors.affiliation: Department of Pathology, Massachusetts General Hospital, Boston, MA.
authors.forename: Martin S
authors.initials: MS
authors.lastname: Taylor
authors.affiliation: Department of Medicine and the Massachusetts General Hospital Cancer Center, Boston, MA.
authors.forename: David T
authors.initials: DT
authors.lastname: Ting
authors.affiliation: McKusick-Nathans Institute of Genetic Medicine (IGM) and kburns@jhmi.edu.|Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Kathleen H
authors.initials: KH
authors.lastname: Burns
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics*; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D020084:Long Interspersed Nucleotide Elements / Q000235:genetics*; D009369:Neoplasms / Q000235:genetics*
chemical_list: D014408:Biomarkers, Tumor; D005819:Genetic Markers