The landmark findings offer researchers a whole trove of new resources to guide future studies on tailored cancer treatments.

Cancer cells can harbor thousands of different and unusual mutations but only a few are known to really drive the development of a tumor. A groundbreaking 2020 study was first to begin seriously cataloguing these mutational signatures but this new research dramatically expands on those prior findings, delivering the most complete picture of what mutations cause the majority of human cancers.

"The reason it is important to identify mutational signatures is because they are like fingerprints at a crime scene - they help to pinpoint cancer culprits," explained Serena Nik-Zainal, a co-author on the new study. "Some mutational signatures have clinical or treatment implications – they can highlight abnormalities that may be targeted with specific drugs or may indicate a potential 'Achilles heel' in individual cancers."

Cataloguing these mutational "fingerprints" allow researchers to home in on particular lifestyle or environmental factors that can cause cancers. For example, prior studies have found a distinct mutation in melanomas can be linked to exposure from ultraviolet (UV) light, so we know for sure that excessive exposure to UV is a powerful cause of skin cancer.

The new study confirmed 51 mutational signatures chronicled in prior studies and found 58 entirely new mutational signatures. The causes behind the majority of these new mutational signatures are unknown and the researchers suggest this indicates there are plenty of factors that can trigger cancer we haven't discovered yet.