Scientists have discovered that a faulty gene is linked to more than half of all breast cancers, it has been announced.
The gene is also thought to be implicated in half of bowel and prostate cancers and a quarter of ovarian and bladder cancers.
The discovery was described as a “major step forward” by cancer charities and is possibly the most important development in cancer gene research in the last 20 years.
Dr Paul Edwards, of the department of pathology at the University of Cambridge, who discovered the gene with colleagues, said it provided “vital information” about how some cancers spread.
The gene, NRG1 (neuregulin-1), is located on chromosome 8, one of the packages of DNA that house genes within a cell.
Experts have noticed that cancerous cells are missing part of chromosome 8 — the section carrying the NRG1 gene.
Normally NRG1 works as a ‘guard’, suppressing cancerous tumours. However, if it is missing or faulty tumours are able to grow.
Dr Edwards and colleagues specifically looked at breast cancer tumours but believe the gene is also linked to other cancers.
Many cases of bowel, prostate, ovarian and bladder cancer are missing the same region of chromosome 8.
He said: “I believe NRG1 could be the most important tumour suppresser gene discovery in the last 20 years as it gives us vital information about a new mechanism that causes breast cancer.
“We found the gene on chromosome 8 partly by good luck and partly by good judgment.
“In every case that we looked at where a big chunk of chromosome 8 had been lost, at least part of the gene was lost. The gene was effectively ‘turned off' in a lot of breast cancers.
“If we have found the gene that is lost on chromosome 8 and we know that some other cancers also lose that bit of chromosome 8, then it is logical that it is the same gene.
“We have got strong evidence that the gene is implicated in breast cancer but we have no reason to think it's not the same for other cancers, including prostate and colon cancer.
“Finding out what genes have been turned off in these cancers is an enormous help in understanding what has gone wrong with their biology.”
Everybody is born with an intact NRG1 but it gets damaged in some people during their lifetime, thereby enabling cancer to develop.
The reason why the gene is damaged and the part of chromosome 8 is lost has not yet been discovered.
However, by identifying the gene experts hope they will be able to target therapies at specific cancers in the future.