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Aberrant CpG-island methylation has non-random and tumour-type-specific patterns.
J F Costello1, M C Frühwald, D J Smiraglia
1[1] Ludwig Institute for Cancer Research, University of California-San Diego, La Jolla, California, USA. jcostello@cc.ucsf.edu
Nature Genetics
|February 2, 2000
Summary
Aberrant CpG island methylation is common in human cancers, affecting hundreds of genes. Specific methylation patterns correlate with tumor type, and reversing methylation can restore gene expression.
Area of Science:
- Genomics
- Epigenetics
- Cancer Biology
Background:
- CpG islands, often found in gene promoters, are typically unmethylated in healthy cells.
- Aberrant CpG island methylation is linked to gene silencing, chromatin condensation, and delayed replication.
- Previous cancer studies focused on limited CpG islands using candidate gene approaches.
Purpose of the Study:
- To conduct a global analysis of CpG island methylation across a large number of human tumors.
- To identify genome-wide methylation patterns and their correlation with specific cancer types.
- To investigate the functional consequences of aberrant CpG island methylation on gene expression.
Main Methods:
- Utilized Restriction Landmark Genomic Scanning (RLGS) to analyze the methylation status of 1,184 CpG islands.
- Examined 98 primary human tumors across various types.
- Correlated methylation patterns with tumor type specificity and gene expression.
Main Results:
- An average of 600 out of 45,000 CpG islands were aberrantly methylated in tumors, even in early stages.
- Identified shared and tumor-specific CpG island methylation patterns.
- Demonstrated reactivation of gene expression upon experimental demethylation in tumor cells.
Conclusions:
- CpG island methylation is a widespread epigenetic alteration in human cancers.
- Specific methylation profiles may serve as biomarkers for distinct tumor types.
- Targeting aberrant methylation could offer therapeutic strategies for cancer treatment.