Scientists have identified proteins in the blood which could warn people of cancer more than seven years before it is diagnosed.
Researchers found 618 proteins linked to 19 types of the disease, including bowel, prostate and breast cancers.
Some 107 of the proteins were found in a group of people whose blood was collected at least seven years before diagnosis.
It is hoped that the findings could help efforts to stop cancer before it starts and be a “crucial first step” towards offering preventative therapies.
The two Cancer Research UK-funded studies from Oxford Population Health suggest the proteins could be involved at the earliest stages of cancer.
Professor Ruth Travis, senior molecular epidemiologist at Oxford Population Health and a senior author of both studies, said: “To be able to prevent cancer, we need to understand the factors driving the earliest stages of its development.
“These studies are important because they provide many new clues about the causes and biology of multiple cancers, including insights into what’s happening years before a cancer is diagnosed.
“We now have technology that can look at thousands of proteins across thousands of cancer cases, identifying which proteins have a role in the development of specific cancers, and which might have effects that are common to multiple cancer types.”
Dr Iain Foulkes, executive director of research and innovation at Cancer Research UK, said: “Preventing cancer means looking out for the earliest warning signs of the disease.
“Discoveries from this research are the crucial first step towards offering preventative therapies which is the ultimate route for giving people longer, better lives, free from the fear of cancer.”
Scientists said further research is needed to find out the exact role the proteins play in cancer development and which are the most reliable ones to test for.
More work would also be needed to identify what tests could be developed to detect the proteins in a clinic and which drugs could target the proteins.
The findings are published in the Nature Communications journal.