How do epigenetic modifications contribute to cancer?

Epigenetic modifications contribute to cancer by altering gene expression and promoting tumour growth.

Epigenetic modifications are changes to the DNA molecule that do not alter the underlying sequence of nucleotides. These modifications can be inherited or acquired throughout an individual's lifetime and can have a significant impact on gene expression. In cancer, epigenetic modifications often result in the silencing of tumour suppressor genes and the activation of oncogenes, promoting uncontrolled cell growth and tumour formation.

One common epigenetic modification in cancer is DNA methylation, where a methyl group is added to a cytosine base in the DNA sequence. This modification often occurs in the promoter region of tumour suppressor genes, preventing their expression and allowing cancer cells to proliferate. Histone modifications, such as acetylation and methylation, can also alter gene expression by changing the accessibility of DNA to transcription factors.

Epigenetic modifications can also contribute to cancer progression by promoting genomic instability. DNA damage response genes, which are responsible for repairing damaged DNA, can be silenced through epigenetic modifications, leading to an accumulation of mutations and chromosomal abnormalities. This can further drive tumour growth and metastasis.

Understanding the role of epigenetic modifications in cancer has led to the development of new therapies targeting these modifications. Epigenetic drugs, such as DNA methyltransferase inhibitors and histone deacetylase inhibitors, have shown promise in clinical trials for the treatment of various cancers. By reversing the epigenetic changes that contribute to cancer, these drugs can restore normal gene expression and slow tumour growth.