Breast cancer

A commonly used blood pressure drug seems to reverse the effect of a gene that has been implicated in up to a fifth of all breast cancers. Recent experiments on mice found that tumours where the AGTR1 gene was overactive shrank by nearly a third when a drug called Losartan was administered.

Stem cells

Experiments on mice have been critical in finding new sources (ie alternatives to embryos) of stem cells, both for experiments and medical applications. When scientists discovered a new type of stem cell that can be made by re-programming skin cells, they needed to know whether it behaved like genuine stem cells. Experiments on mice have been used to demonstrate that they do – most recently these new stem cells were used to successfully clone mice.

Blindness

A drug made from mouse anti- bodies has been found to slow the progression of a form of age-related macular degeneration, a major cause of blindness. In the disease, excessive amounts of blood vessels grow at the back of the eye, which then leak and cause damage to healthy tissue. The drug Lucentis inhibits a chemical messenger required for the eye to grow new blood vessels.

Gene therapy

Mice have been used to develop the next generation of medical treatments. Using hollow nanometre-sized particles of silver to deliver DNA into cells of mice, scientists have managed to reverse some of the symptoms of haemophilia. Gene therapy such as this can compensate for the effects of diseases caused by mutated DNA by delivering a "correct" copy of the genetic material to a site in the body.

Autism

In June, scientists found further evidence that more than one gene is involved in people with genetic-based autism. They found two genes in mice that, when mutated, caused autism-like symptoms. The genes interacted to affect brain growth and sociability.

• Sources: understandinganimalresearch.org.uk pro-test.org.uk