SCIENTISTS in the region have made a stunning breakthrough which could lead to a cure for cervical cancer - the second most common form of the disease in women.

It kills about 1,250 women in the UK every year and thousands more worldwide.

Professor Jo Milner, one of the York University team which made the discovery described the breakthrough as "absolutely remarkable".

The York scientists astonished the cancer world by succeeding in killing human cervical cancer cells without damaging healthy cells.

It could lead to the development of an ointment which could be applied locally if signs of cervical cancer are detected.

Currently, the only way to treat cervical cancer is through conventional methods such as surgery, radiotherapy or chemotherapy.

The new treatment works by knocking out two aggressive viral genes which destroy the body's defences and cause infected cells to reproduce uncontrollably.

The implications of the research, carried out by Prof Milner and Dr Ming Jiang, are even more widespread.

Prof Milner said last night that she was "optimistic" that the unique form of gene therapy developed by the York team could work with other cancers triggered by viruses.

"We are already looking at other tumours now," she said. "Several types are caused by viruses, including certain types of lymphoma and certain types of leukaemia. They should be targetable as well."

Cervical cancer is triggered by a human virus which may lay dormant for some years.

The virus attacks the body's two lines of defence - its two tumour suppressors, the proteins p53 and RB.

In normal cells, RB controls cell division and multiplication, while p53 has the ability to kill damaged cells that might become cancerous.

The cervical cancer virus takes over the reins of cell growth resulting in out-of-control cell division.

Dr Jiang and Prof Milner decided to use a new technique called RNA interference to try to knock out the viral genes in the infected cells and restore the body's normal defence mechanism.

It was the first time that this approach had been tried with mammal cells.

The treatment - which uses a tiny man-made molecule - knocked out the E6 viral gene causing the growth of the tumour cells to slow down.

But what amazed them was when the second viral gene - E7 - was knocked out, all of the remaining cancer cells died.

It became even more remarkable when follow-up experiments showed that the anti-viral treatment had no effect on the normal growth and behaviour of non-infected human cells.

Prof Milner said the successful elimination of cancer cells without damaging surrounding tissue was very exciting.

"There is no reason to think that this small molecule will have any adverse side-effect on human cells but more lab work is necessary before we get into clinical trials," she added.

Elaine King, chief executive of Yorkshire Cancer Research, the charity which funded the work, said: "This really is encouraging news and proves once again that the research we fund in Yorkshire really is world class."

Researchers in the US have found that RNA interference is showing promising results in protecting cells from infection with the virus which causes HIV and Aids.

The research is published today in the journal Oncogene.