A massive study has analyzed the genomes of cancer cells from more than 12,000 patients, identifying 58 new mutational signatures that offer clues to novel causes of cancer. 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.
Between this new study and the 2020 work, researchers are confident they have now discovered most of the mutational signatures that drive the development of common cancers. It is thought that what is still unknown accounts for rarer forms of cancer covering less than one percent of tumors.
At this point, the research is more an academic achievement than a pragmatic one. However, building this body of knowledge moving forward could help inform profoundly valuable research discoveries such as new understandings into environmental exposures that cause cancer.
This library of mutational signatures also helps researchers understand the mechanisms that drive the development of particular tumors. Knowing how these cancers develop helps researchers test ways to therapeutically target those pathways, creating new and more personalized cancer treatments.
“Mutational signatures are an example of using the full potential of WGS (whole-genome sequences),” said Matt Brown, from Genomics England. “We hope to use the mutational clues seen in this study and apply them back into our patient population, with the ultimate aim of improving diagnosis and management of cancer patients.”
The new study was published in the journal Science.
Source: University of Cambridge