Effective treatment for soft tissue sarcoma (rhabdomyosarcoma)

Jul 15 2004

Rhabdomyosarcoma is a highly malignant aggressive form of soft tissue cancer in children, the causes of which are currently unknown. Although the fibrous growths can be found all over the body they commonly develop around the head, neck, bladder and testes in young boys.

The most common age for onset is between 1-5 years of age. The treatments used are usually chemotherapy using a combination of drugs, radiotherapy and surgery and although quite effective (66% success rate at present), the side affects commonly experienced by the young patients are very unpleasant and the whole process can prove to be very traumatic not only for the patient but for the families too. So there is a need for a better way of treating the disease.

At present the cocktail of drugs administered through the chemotherapy route are not selective to the cancer cells and so they also attack healthy cells. In order for the treatment to be effective without causing unnecessary tissue damage, researchers have been looking for ways to specifically target the cancer cells in order to deliver the therapeutic agent that will kill the tumour.

An unexpected link between rhabdomyosarcoma and a particular form of a disease known as myasthenia gravis was recently discovered by University scientists. Research was being carried out at the University of Oxford amongst women suffering from spontaneous miscarriages caused by an autoimmune response to their own foetus. It was then discovered that the mothers were producing antibodies against a molecule on the surface of the foetal cells which was the same as that present on the surface of the rhabdomyosarcoma cells. Scientists at the University of Würzburg then made molecules that were smaller fragments of the antibody but which would still have the same attraction for the rhabdomyosarcoma cells as for the original antibody. A gene that encodes the fragments was then transferred into a bacteria containing the DNA for a toxin. An immunotoxin was then produced containing the antibody fragment and the toxin together which is able to target the sarcoma cells using the antibody fragment and kill them with the toxin.

The immunotoxin has already been tested in a good model system and the positive results achieved have been able to show the therapeutic potential of the technique. The antibody fragment is also able to carry other toxins or even radioactive elements such as Yttrium for delivery to the site of a tumour.

Dr Richard Middleton, the project manager from Isis Innovation Ltd, the technology transfer company for the University of Oxford stated, “This is excellent science leading to an application which may be of real benefit to people in an area of currently unmet need”.

http://www.isis-innovation.com