Genetic defect triples death risk of prostate cancer victims
MEN with prostate cancer are three times more likely to die from it if they have a particular genetic mutation.
Up to one in five patients may have a genetic quirk which worsens their chances of survival and makes them more likely to relapse.
Most men with prostate cancer do not die from it, but scientists sought to find those with advanced cancer who were at greatest risk. In a study of 429 men at this stage of cancer, they found those with a mutated gene called RB1 in their tumour were 3.3 times more likely to die.
The genetic study is the largest ever carried out for advanced prostate cancer and could help doctors identify men with very aggressive cancer and target them with different treatment.
Co-author Professor Johann de Bono of the Institute of Cancer Research in London said: ‘Our study really got under the bonnet of prostate cancer to understand the “engine” driving tumour growth and explore how a range of genes affect the disease and its response to treatment.
‘We identified one particular genetic mutation that seems to indicate that tumours are going to be very aggressive, and that the affected men need the most intensive treatment we have available.’
Prostate cancer has gained attention lately from actor Stephen Fry and presenter Bill Turnbull talking about their experiences with the disease, while the Daily Mail has long campaigned for improved treatments and diagnosis.
Only one in 41 men with prostate cancer die, raising the question of whether patients’ odds of survival are determined by the genes in their tumour.
Researchers from Europe and the US examined 444 tumour samples from men with advanced prostate cancer, finding RB1 affected survival.
RB1, or the retinoblastoma gene, is sonamed because mutations in it cause a rare eye cancer in children called retinoblastoma. But it can also keep tumour cells in check so they can’t grow and spread too aggressively or mutate to resist treatment.
Men with a mutation in the gene are thought to miss out on that protection.
Tracking the patients whose tumours they analysed, researchers found those with an RB1 mutation were 6.6 times more likely to relapse after going into remission with prostate cancer.
They were 3.3 times more likely to die than men without a mutation receiving the same standard treatment of the drugs abiraterone and enzalutamide.
It is thought that 10 to 20 per cent of men with prostate cancer have an RB1 mutation.
The study, published in the journal Proceedings of the National Academy of Sciences, found mutations in two further genes linked to a risk of relapse.
They found that men with a genetic mutation which makes them respond well to immunotherapy treatment also tended to have mutations in the genes CDK4 and CCND1. These genes respond to a breast cancer drug called palbociclib, so this may lead to a better treatment for this group of patients.