UNSW medical scientists have discovered that DNA repair is compromised at important regions of our genome, shedding new light on the human body’s capacity to repair DNA damage.
Repairing damage in DNA from anything that causes a mutation, such as UV radiation and tobacco smoke, is a fundamental process that protects our cells from becoming cancerous.
In the study published today in the journal Nature, the scientists analysed more than 20 million DNA mutations from 1,161 tumours across 14 cancer types. They found that in many cancer types, especially skin cancers, the number of mutations was particular high in regions of the genome known as ‘gene promoters’. Significantly, these DNA sequences control how genes are expressed which in turn determine cell type and function.
The researchers showed that the numbers of DNA mutations are increased in gene promoters because the proteins that bind DNA to control gene expression block one of our cell repair systems responsible for fixing damaged DNA. This system is known as nucleotide excision repair (NER) and is one of a number of DNA repair mechanisms that occurs in human cells and the only one capable of repairing damage from UV light.