Adult cancer could start in childhood
Chance to stop disease decades early
CANCER may start in childhood – decades before sufferers fall ill, a breakthrough study has found.
It raises hopes that Britons could be screened for the disease as children and prevented from developing it.
A major genetic mutation which leads to ovarian cancer is now known to happen ten to 20 years before the average woman falls ill – and, in very rare cases, 50 years earlier.
The same type of mutation may start as early as 20 years before women are diagnosed with breast cancer.
Scientists have also found mutations, in the brain cancers glioblastoma and medulloblastoma, which might even begin in the womb. Medulloblastoma only affects children.
The findings could mean the window to stop the disease is decades earlier than thought.
More than 1,300 researchers from 37 countries looked at 38 types of cancer, most of which are believed to start up to a decade before someone falls ill, and three of which could potentially begin in childhood.
Their findings form part of the Pan-Cancer Analysis of Whole Genomes project, which analysed more than 2,600 genomes from 38 tumour types.
Dr Peter Van Loo of London’s Francis Crick Institute who, coauthored the study, said: ‘It is science fiction currently but one could envisage one day detecting cancer in children and treating it by killing the problematic cells. A very specific drug would be needed without side effects, so it is not likely to happen soon but could be possible one day.’
Experts found the mutations that cause cancer to start growing happen two to ten years before symptoms for most of the 38 types studied.
On average, ovarian cancer started ten to 20 years before tumours were found. But in one or two cases, it appeared as if it started 40 to 50 years before symptoms showed.
Scientists knew this because at an early stage of cancer, two pairs of identical chromosomes appear which experts think is to help the cells turn cancerous and clump into tumours. It is possible to see when this happened because mutations in cells happen at a fairly steady rate. If a cell which created a set of chromosomes to become cancer creates ten mutations a year and has 100 mutations, the chromosomes were created ten years earlier.
The study authors say their results are still estimates, but across the 38 cancers the early mutations which appeared to drive them happened mostly in nine genes. This could make a treatment easier to find. Professor Peter Johnson, NHS national clinical director for cancer, said: ‘Finding ways to turn research like this into tests we can use in the clinic could revolutionise when and how we diagnose cancer in the future.’
The research, which took more than a decade and has seen 23 scientific papers published, compared the DNA from patients’ tumours to that found in their non-cancerous cells.
It is now possible to categorise almost every genetic change found in a cancer and the processes causing those mutations.
The analysis provides yet more evidence that no two people have the same cancer and each has an individual genetic code.
The technology to sequence that genetic code costs thousands of pounds, but experts hope in future it will be cheaper. That could enable people to be given tailored treatment.
Someone is diagnosed with cancer every two minutes in the UK, with 363,000 cases a year.