Spread of cancer blocked

Cancer cells are sticky

Scientists have successfully blocked the spread of human breast cancer implanted into mice.

If breast cancer - and other forms of the disease - can be stopped from spreading around the body, then many lives could be saved.

A team from the San Francisco VA Medical Center were able to stop the cancer in its tracks by using a modified version of a naturally occurring human protein.

The treatment appeared to be side effect free.

What we're trying to do is make cancer a disease that one can live with

Dr Constance John

It works by reducing the "stickiness" of cancer cells. It is the ability to adhere to other cells that allows a cancer cell that breaks away from a primary tumour to lodge in other parts of the body, and trigger the growth of new malignancies.

Researcher Dr Constance John said: "We're not trying to develop a cure for cancer.

"What we're trying to do is make cancer a disease that one can live with."

Modification

The new technique involves the modification of a human protein called galectin-3, which plays a crucial role in making cancer cell sticky.

The researchers effectively robbed the protein of this ability by changing its structure.

They then implanted portions of human-derived breast cancer tumours into mice with weakened immune systems.

Once the tumours were established, some mice were injected with the modified protein, and others were given a dummy treatment.

By the end of the experiment, cancer had spread to lymph nodes or other organs in 11 of the 20 mice given the dummy injection - but only four of the 20 who received the modified protein.

In addition, the original implanted cancer fragments had grown significantly less in the "treated" mice.

The researchers hope that a drug therapy based on their findings may one day be used in combination with currently available cancer medications.

Lead researcher Dr Gary Jarvis said: "If we can stop metastasis (spread) in humans, we will have gone a long way towards successfully treating cancer."

Martin Ledwick, senior cancer information nurse for the charity CancerBACUP, said: "These experiments are interesting, but people should not get over-excited.

"It will be a long time before we know whether this study is at all relevant for the treatment of cancer in humans."

Anna Wood, a policy analyst for the charity Breast Cancer Care, echoed this opinion.

She said: "This treatment has only been tested on mice and we would advice caution when interpreting the results."

The research is published in the journal Clinical Cancer Research.