Cells (Sep 2020)

Aberrant Methylation of LINE-1 Transposable Elements: A Search for Cancer Biomarkers

  • Anastasia A. Ponomaryova,
  • Elena Y. Rykova,
  • Polina A. Gervas,
  • Nadezhda V. Cherdyntseva,
  • Ilgar Z. Mamedov,
  • Tatyana L. Azhikina

DOI
https://doi.org/10.3390/cells9092017
Journal volume & issue
Vol. 9, no. 9
p. 2017

Abstract

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Cancer remains one of the main causes of human mortality despite significant progress in its diagnostics and therapy achieved in the past decade. Massive hypomethylation of retrotransposons, in particular LINE-1, is considered a hallmark of most malignant transformations as it results in the reactivation of retroelements and subsequent genomic instability. Accumulating data on LINE-1 aberrant methylation in different tumor types indicates its significant role in cancer initiation and progression. However, direct evidence that LINE-1 activation can be used as a cancer biomarker is still limited. The objective of this review was to critically evaluate the published results regarding the diagnostic/prognostic potential of the LINE-1 methylation status in cancer. Our analysis indicates that LINE-1 hypomethylation is a promising candidate biomarker of cancer development, which, however, needs validation in both clinical and laboratory studies to confirm its applicability to different cancer types and/or stages. As LINE-1 is present in multiple cell-free copies in blood, it has advantages over single-copy genes regarding perspectives of using its methylation status as an epigenetic cancer biomarker for cell-free DNA liquid biopsy.

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