The defective gene was found in about a third of tumour samples of the most lethal form of brain cancer, glioblastoma multiforme. Similar gene mutations were seen in some prostate and breast cancer cells.
The gene, known as PTEN, is believed to be involved in controlling cell growth, preventing the kind of rampant cell division that leads to cancer.
It is thought mutations in the cancerous gene may deactivate it, allowing tumours to develop.
The findings, from a team of researchers led by Jing Li, of Columbia University College of Physicians and Surgeons in New York, were published yesterday in the American journal Science.
Dr Denise Sheer, a senior scientist with the Imperial Cancer Research Fund in the UK, said last night: "If indeed this gene does turn out to be one of the genes involved in glioblastoma, then the finding is of critical importance and a major discovery.
"Potentially it may offer possible targets for the development of treatments, although that will be some time into the future."
Glioblastoma multiforme kills between 5,000 and 6,000 people a year in the United States. There are no similar figures available in the UK, but all types of brain and central nervous system tumours together account for about 2 per cent of deaths in Western countries. Their overall incidence is between one and 15 deaths per 100,000 of population.Reuse content