A genetically-modified virus that exploits the selfish behaviour of cancer cells may offer a powerful and selective way of killing tumours. Deleting a key gene from the virus enabled it to infect and burst cancer cells while leaving normal tissues unharmed, reveals a study by researchers at Cancer Research UK and Queen Mary's School of Medicine and Dentistry, University of London. Viruses spread by infiltrating the cells of their host. Normally, the detection of an intruder by a cell triggers a process called apoptosis, which causes the cell to commit suicide and prevents the virus spreading further. However, viruses can carry genes that allow them to slip past this cell death process in normal cells, causing infection. The UK researchers deleted one such gene in an adenovirus. This meant that the virus was immediately detected by normal cells and was unable to spread. But in cancer cells, which grow uncontrollably and ignore the cell death process, the virus was able to thrive and spread rapidly. It then multiplied so vigorously that it killed the cancer cells by making them explode. "The great thing about this strategy is that the cancer cell does all the hard work," says Nick Lemoine, director of the Cancer Research UK Clinical Centre at Bart's Medical School, who led the team. "It makes more and more virus to infect its neighbouring cancer cells. But if a normal cell is infected, it commits suicide before it can make new virus and spread of the virus is contained." Source: New Scientist