People with a particular gene may be less likely to need cancer treatment, new research suggests.
A study by researchers at University College London's Institute of Child Health found that people with cancer are less likely to carry two variants of the B-MYB gene.
The gene is carried by up to half of the world's population, the paper published in Oncogene journal suggests.
Researchers studied more than 400 patients with bowel cancer, neuroblastoma or chronic myeloid leukaemia.
They compared these patients' version of the B-MYB gene with the versions found in 230 cancer-free volunteers, and found that the cancer patients were half as likely to carry the gene variants in question.
Researcher Dr Arturo Sala told the BBC: "This would suggest that we have found a key player in the genetic influences in cancer. People who carry these gene variants might well be protected against cancer."