Discovery could outwit cancer cells

Treatments could be made more effective

More effective cancer therapies may be possible after researchers discovered how cancer cells are fending off attacks.

The scientists at Ohio State University believe that certain cancer cells are producing their own growth-promoting chemicals.

These help the cells spread to different parts of the body and resist chemotherapy courses.

The researchers hope that drugs which block the action of the "growth factors" will vastly improve the effectiveness of other treatments.

Lung cancer is one of the hardest cancers to treat, with both chemotherapy and radiotherapy proving ineffective in most cases.

An earlier study by the same scientists found that tumours growing just under the skin of laboratory rats was far more sensitive to chemotherapy than similar tumours in the lung and lymphatic system.

The drug resistant tumours were discovered to have high levels of two growth factor chemicals.

When produced in combination, drug resistance in tumour cells increased up to 10 times.

Human lung tumours reduced

The resistance was broad - three difference classes of anti-cancer drug were affected.

When drugs known to inhibit the production of these growth factors were used, the sensitivity of the tumours was increased.

Further animal studies using human lung cancers seemed to support the theory, as chemotherapy was more effective when the growth factors were blocked.

Tests in humans with lung cancer will start later this year, it is hoped.

Professor Jessie Au, who led the project, published in the Proceedings of the National Academy of Sciences, said: "Based on what we have seen in animals, we believe that this drug can make a person's tumour more sensitive to traditional chemotherapeutic drugs."

If the effectiveness of the chemotherapy could be boosted, lower doses could be used, and the toxic effects on the human body reduced.

A spokesman for the Imperial Cancer Research Fund described it as an "interesting" finding.

He said: "One of the biggest challenges we face when treating cancer is the ability of cancer cells to develop resistance to specific chemotherapies.

"The University of Ohio team's discovery could lead to more effective treatments."