Early signs of cancer can show up years or even decades before diagnosis, researchers have discovered.
The study, based on samples from more than 2,500 tumours and 38 cancer types, suggests there is a longer-than-expected window in which patients could be tested and treated at the earliest stages of the disease.
Peter Van Loo, co-lead author, based at the Francis Crick Institute, said unlocking these patterns means it should now be possible to develop new diagnostic tests that pick up signs of cancer much earlier.
The study revealed that about half of the earliest mutations occurred in just nine genes, meaning there is a relatively small pool of common genes that serve as triggers for cells to diverge from healthy development to a path towards cancer.
“One could try and identify these [early mutations] and do some kind of very sensitive imaging on patients that were positive,” said Van Loo. “Or even further into the future, one could conceive of methods that really targeted these cells and made them light up in an imaging approach or just kill them in one go.”
Human cells undergo billions of mutations, but only a small number of them, called driver mutations, give rise to cancer.
The researchers looked at how many times a driver mutation had been replicated and copied across chromosomes.
Using a “carbon-dating method”, they were able to reconstruct the order in which the genomes of cancer cells started to accumulate errors and eventually carry large segments that had been scrambled or copied.
The team found that these mutations occurred particularly early in ovarian cancer as well as in two types of brain tumour, glioblastoma and medulloblastoma, the Guardian reports.
The work was carried out as part of the Pan-Cancer Analysis of Whole Genomes project, the most comprehensive study of cancer genetics to date.