(From bio.com). In a clever piece of work, scientists have demonstrated that the natural mechanisms of stem cells can be used to deliver gene therapy to tumors in the body. "The researchers then used a virus to deliver a particular gene that has therapeutic action against cancer into the stem cells. When given back through an intravenous injection, the millions of engineered mesenchymal progenitor cells engraft where the tumor environment is signaling them, and then activate the therapeutic gene." This is quite ingenious, utilitizing the normal stem cell response to injury that has been subverted by cancer in order to grow tumors. "This drug delivery system is attracted to cancer cells no matter what form they are in or where they are."