Latest trial of a virus engineered to kill cancer shows promise

http://arstechnica.com/science/2013/02/latest-trial-of-a-virus-engineered-to-kill-cancer-shows-promise/     / scientists working engineer virus attack cancer basic idea is sound promising-looking results tumor shrinking infection viruses small trials companies Medicine promising results different approach ensuring virus leads death of cancer cells revs immune system to attack them result clinic opportunity review general approach of treating cancer with viruses basic idea leverage decades common viruses research has identified a variety of mutations keeping viruses from growing in normal cells inject virus into a healthy individual it won't be able to infect any of their cells cancer cells are different carry a series of mutations of their own p53 protein normally induces aberrant cells to undergo an orderly death called apoptosis shut down the growth of viruses in a cell some viruses encode a protein that inhibits p53 damage eliminate copies of p53 so that it doesn't cause them to undergo apoptosis virus p53 inhibitor deleted can't grow in normal cells hey have p53 can grow in cancer cells eliminated their p53 cancer-killing virus great idea viruses dropped after preliminary trials new trial similar approach vaccinia smallpox used for vaccines carries a gene essential make copies of itself researchers have engineered a version without that gene ensuring can't grow in normal cells gene shut down cancer cells reactivate the gene hospitable environment mutant virus researchers insert inserting gene molecule recruit immune cells granulocyte-macrophage colony-stimulating factor GM-CSF immune system plays an important role in controlling cancer doesn't always generate a full-scale response to cancer bring immune cells to the site of the cancer and activate them creating a more aggressive immune response to any cells that survive viral infection study checking tolerance two different doses virus tolerated well tolerate subjects reported bout of flu-like symptoms only one subject out of 30 had a more severe response tumors did respond placebo-controlled trials low-dose group survival time higher dose group imaging of tumors showed lots of dead cells tests immune system virus generated robust response clinical trials company engaged in phase 2 trials designed identify treatment large-scale effectiveness trial promising results /