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Gene therapy cancer treatment success Tuesday, 1 August, 2000, 08:03 GMT 09:03 UK - A gene treatment injected directly into malignant tumours causes many to shrink, and some to disappear altogether. The study, published in the journal Nature Medicine, is encouraging news for those who believe that these kinds of treatment could be used to target many different types of cancer. In this case, 30 British and US patients suffering from head and neck cancer - which proves fatal in a third of cases - were treated with a modified common cold virus called ONYX-015. This looked for a key genetic difference between cancer cells and healthy cells - in this case a relative deficiency of a gene called p53 - only destroying those lacking the gene. This treatment was combined with standard chemotherapy, but the eventual results were better than those normally obtained by chemotherapy alone. Tumours shrank in 25 out of 30 patients. In only 17% of the patients did the tumours progress. In eight patients, the tumour disappeared completely - and had not returned by the time the trial reported. This is an improvement over previous tests using only gene therapy, in which the tumours disappeared - but swiftly returned when treatment ended. Dr French Anderson, of the Gene Therapy Laboratories at the University of Southern California in Los Angeles, said that this was the first successful larger scale trial of a gene therapy. He said: "ONYX-015 may be able to sensitise infected and uninfected cells to killing by chemotherapy." It is thought that between 45% and 70% of head and neck tumour cells have mutations in the p53 gene, which normally helps the body repair damage that can lead to cancer. There were side-effects, with some patients reporting flu-like symptoms, including fever, weakness and chills. This treatment differs from many other gene therapies in that it does not seek to replace a damaged gene with a working copy in cells, but instead homes in on the deficient cell and works to destroy it. Head and neck cancers are an obvious target for gene therapy, as their proximity to the skin surface makes it easier to inject the treatment directly into it. To reach less accessible tumours - or treat cancers which could be anywhere in the body - much larger doses of the therapy would have to be given. There are still significant safety worries about larger doses, and it was a high dose of gene therapy which may have contributed to the death of a US man suffering from severe liver cancer. "http://news.bbc.co.uk/low/english/health/newsid_861000/861136.stm" janet paterson 53 now / 41 dx pd / 37 onset pd / 44 dx cd / 43 onset cd tel: 613 256 8340 url: "http://www.geocities.com/janet313/" email: "[log in to unmask]" smail: PO Box 171 Almonte Ontario K0A 1A0 Canada