Thousands of men with advanced prostate cancer have been given new hope of a cure after scientists discovered the genetic cause behind 90 per cent of tumours.
Nine out of 10 cases of late stage prostate cancer can now be linked to changes in the DNA of patients.
In some cases, drugs being used for other cancers will also tackle these genetic defects.
Scientists said the breakthrough was like uncovering the "Rosetta Stone" for prostate cancer, in reference to the stone tablet which helped Egyptologists break the code of hieroglyphics.
The study was led in Britain by scientists at the Institute of Cancer Research, London, in collaboration with researchers from eight academic clinical trial centres around the world.
Researchers said doctors could now start testing for the mutations and give patients with advanced prostate cancer existing drugs or drug combinations to target the specific genomic aberrations.
"Our study shines new light on the genetic complexity of prostate cancer as it develops and spreads, revealing it to be not a single disease, but many diseases each driven by their own set of mutations," said Johann de Bono, professor of experimental cancer medicine at the Institute of Cancer Research, London.
"We're describing this study as prostate cancer's Rosetta Stone because of the ability it gives us to decode the complexity of the disease, and to translate the results into personalised treatment plans for patients."
Doctors from the Royal Marsden and hospitals in the United States studied the genetic make-up of 150 tumours from patients with advanced prostate cancer and a slim chance of survival.
Nearly two thirds of the men in the study had mutations in a molecule that interacts with the male hormone androgen.
About 20 per cent of patients also had mutations in the BRCA1 and BRCA2 genes, which increase the risk of breast and ovarian cancer and there are already drugs to help.
The researchers also found that some people are born with genes which predispose them to prostate cancer, meaning screening programmes could be effective at preventing the disease.
In the next phase of the study, researchers will genetically sequence tumour cells from at least 500 patients and follow the course of their disease to see how they respond to personalised treatments.