What is DNA Methylation?
DNA methylation is a biochemical process involving the addition of a methyl group to the DNA molecule, typically at the cytosine base of a CpG dinucleotide. This modification can regulate gene expression without altering the DNA sequence itself. DNA methylation plays a crucial role in various biological processes, including gene expression, embryonic development, and genomic stability.
How Does DNA Methylation Affect Gene Expression?
DNA methylation generally represses gene expression. When methyl groups are added to the promoter regions of genes, they can block the binding of transcription factors and other regulatory proteins, thereby silencing the gene. Conversely, the removal of methyl groups, known as
demethylation, can activate gene expression.
Why is DNA Methylation Important in Cancer Diagnosis?
DNA methylation patterns serve as valuable biomarkers for cancer diagnosis, prognosis, and treatment response. For instance, hypermethylation of the
MGMT gene promoter is often used as a predictive marker in glioblastoma. Similarly, the methylation status of the
BRCA1 gene can provide insights into breast cancer risk and treatment options.
What Are the Challenges in Studying DNA Methylation in Cancer?
One of the primary challenges in studying DNA methylation in cancer is the complexity and heterogeneity of methylation patterns. Cancer is a highly heterogeneous disease, and methylation changes can vary significantly between different types and even within the same type of cancer. Additionally, distinguishing between causative methylation changes and those that are merely a consequence of cancer progression remains a significant challenge.
