Cancer cells have been programmed back to normal by scientists in a breakthrough which could lead to new treatments and even reverse tumour growth.

For the first time, aggressive breast, lung and bladder cancer cells have been turned back into harmless benign cells by restoring the function which prevents them from multiplying excessively and forming dangerous growths.

Scientists at the Mayo Clinic in Florida in the U.S. said it was like applying the brakes to a speeding car.

So far it has only been tested on human cells in the lab, but the researchers are hopeful that the technique could one day be used to target tumours so that cancer could be “switched off” without the need for harsh chemotherapy or surgery.

“We should be able to re-establish the brakes and restore normal cell function,” said Prof Panos Anastasiadis, of the Department for Cancer Biology.