LINE-1 hypomethylation in blood and tissue samples as an epigenetic marker for cancer risk: a systematic review and meta-analysis.

<h4>Objective</h4>A systematic review and a meta-analysis were carried out in order to summarize the current published studies and to evaluate LINE-1 hypomethylation in blood and other tissues as an epigenetic marker for cancer risk.<h4>Methods</h4>A systematic literature sea...

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Main Authors: Martina Barchitta, Annalisa Quattrocchi, Andrea Maugeri, Manlio Vinciguerra, Antonella Agodi
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2014-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0109478
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author Martina Barchitta
Annalisa Quattrocchi
Andrea Maugeri
Manlio Vinciguerra
Antonella Agodi
author_facet Martina Barchitta
Annalisa Quattrocchi
Andrea Maugeri
Manlio Vinciguerra
Antonella Agodi
author_sort Martina Barchitta
collection DOAJ
description <h4>Objective</h4>A systematic review and a meta-analysis were carried out in order to summarize the current published studies and to evaluate LINE-1 hypomethylation in blood and other tissues as an epigenetic marker for cancer risk.<h4>Methods</h4>A systematic literature search in the Medline database, using PubMed, was conducted for epidemiological studies, published before March 2014. The random-effects model was used to estimate weighted mean differences (MDs) with 95% Confidence Intervals (CIs). Furthermore, subgroup analyses were conducted by sample type (tissue or blood samples), cancer types, and by assays used to measure global DNA methylation levels. The Cochrane software package Review Manager 5.2 was used.<h4>Results</h4>A total of 19 unique articles on 6107 samples (2554 from cancer patients and 3553 control samples) were included in the meta-analysis. LINE-1 methylation levels were significantly lower in cancer patients than in controls (MD: -6.40, 95% CI: -7.71, -5.09; p<0.001). The significant difference in methylation levels was confirmed in tissue samples (MD -7.55; 95% CI: -9.14, -65.95; p<0.001), but not in blood samples (MD: -0.26, 95% CI: -0.69, 0.17; p = 0.23). LINE-1 methylation levels were significantly lower in colorectal and gastric cancer patients than in controls (MD: -8.33; 95% CI: -10.56, -6.10; p<0.001 and MD: -5.75; 95% CI: -7.75, -3.74; p<0.001) whereas, no significant difference was observed for hepatocellular cancer.<h4>Conclusions</h4>The present meta-analysis adds new evidence to the growing literature on the role of LINE-1 hypomethylation in human cancer and demonstrates that LINE-1 methylation levels were significantly lower in cancer patients than in control samples, especially in certain cancer types. This result was confirmed in tissue samples, both fresh/frozen or FFPE specimens, but not in blood. Further studies are needed to better clarify the role of LINE-1 methylation in specific subgroups, considering both cancer and sample type, and the methods of measurement.
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spelling doaj-art-e8ee4479ace64721aa94fe10ab5872cf2025-08-20T03:31:34ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-01910e10947810.1371/journal.pone.0109478LINE-1 hypomethylation in blood and tissue samples as an epigenetic marker for cancer risk: a systematic review and meta-analysis.Martina BarchittaAnnalisa QuattrocchiAndrea MaugeriManlio VinciguerraAntonella Agodi<h4>Objective</h4>A systematic review and a meta-analysis were carried out in order to summarize the current published studies and to evaluate LINE-1 hypomethylation in blood and other tissues as an epigenetic marker for cancer risk.<h4>Methods</h4>A systematic literature search in the Medline database, using PubMed, was conducted for epidemiological studies, published before March 2014. The random-effects model was used to estimate weighted mean differences (MDs) with 95% Confidence Intervals (CIs). Furthermore, subgroup analyses were conducted by sample type (tissue or blood samples), cancer types, and by assays used to measure global DNA methylation levels. The Cochrane software package Review Manager 5.2 was used.<h4>Results</h4>A total of 19 unique articles on 6107 samples (2554 from cancer patients and 3553 control samples) were included in the meta-analysis. LINE-1 methylation levels were significantly lower in cancer patients than in controls (MD: -6.40, 95% CI: -7.71, -5.09; p<0.001). The significant difference in methylation levels was confirmed in tissue samples (MD -7.55; 95% CI: -9.14, -65.95; p<0.001), but not in blood samples (MD: -0.26, 95% CI: -0.69, 0.17; p = 0.23). LINE-1 methylation levels were significantly lower in colorectal and gastric cancer patients than in controls (MD: -8.33; 95% CI: -10.56, -6.10; p<0.001 and MD: -5.75; 95% CI: -7.75, -3.74; p<0.001) whereas, no significant difference was observed for hepatocellular cancer.<h4>Conclusions</h4>The present meta-analysis adds new evidence to the growing literature on the role of LINE-1 hypomethylation in human cancer and demonstrates that LINE-1 methylation levels were significantly lower in cancer patients than in control samples, especially in certain cancer types. This result was confirmed in tissue samples, both fresh/frozen or FFPE specimens, but not in blood. Further studies are needed to better clarify the role of LINE-1 methylation in specific subgroups, considering both cancer and sample type, and the methods of measurement.https://doi.org/10.1371/journal.pone.0109478
spellingShingle Martina Barchitta
Annalisa Quattrocchi
Andrea Maugeri
Manlio Vinciguerra
Antonella Agodi
LINE-1 hypomethylation in blood and tissue samples as an epigenetic marker for cancer risk: a systematic review and meta-analysis.
PLoS ONE
title LINE-1 hypomethylation in blood and tissue samples as an epigenetic marker for cancer risk: a systematic review and meta-analysis.
title_full LINE-1 hypomethylation in blood and tissue samples as an epigenetic marker for cancer risk: a systematic review and meta-analysis.
title_fullStr LINE-1 hypomethylation in blood and tissue samples as an epigenetic marker for cancer risk: a systematic review and meta-analysis.
title_full_unstemmed LINE-1 hypomethylation in blood and tissue samples as an epigenetic marker for cancer risk: a systematic review and meta-analysis.
title_short LINE-1 hypomethylation in blood and tissue samples as an epigenetic marker for cancer risk: a systematic review and meta-analysis.
title_sort line 1 hypomethylation in blood and tissue samples as an epigenetic marker for cancer risk a systematic review and meta analysis
url https://doi.org/10.1371/journal.pone.0109478
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