DNA damage occurs in all cellular organisms. In human cells, it can be caused by the body’s normal metabolic activities, by environmental factors or by chemotherapy. During the crucial phase when cells replicate their genetic content, they are susceptible to lesions – damaged sections of a DNA molecule. Common lesions known as DNA-protein cross-links (DPCs) can prevent the cell from replicating itself and may lead to genome instability, a cause of cancer and ageing.