London, Oct 5 : Scientists at Memorial Sloan-Kettering Cancer Centre in New York City have found out why some women suffer relapses years after beating breast cancer.

Leading oncologist Dr. Larry Norton has revealed that breast cancer cells have the unique ability to lie dormant for years, even after the original tumour has been removed.

In a novel study, the researchers have found a genetic switch, called Src, that triggers dormant breast cancer cells.

"Wandering cells might relocate to the primary site just as they could - by using the same biological toolbox - locate to a distant site," the Daily Express quoted Norton as saying.

"It's just as a weed-bed overgrows and destroys a garden and then scatters its tiny seeds to invade neighbouring gardens.

"Our results should encourage cancer specialists to think about further study of Src inhibitor drugs that attack reservoirs of these `wandering' latent cancer cells and prevent spread of the disease in breast cancer patients after the tumour has been removed," he added.

Dr. Helen George, Cancer Research UK's head of science information, said: "This research is important because it offers an explanation of why some breast cancers can spread and return. (ANI)