Stem Cell Transplant News
Stem cell transplants are commonly used for patients with cancer so that they can receive new blood-producing stem cells after the existing ones are killed by chemotherapy. Patients can receive stem cells from donors, which means there is a possibility of rejection by the body in the form of Graft Versus Hosts Disease (leukemia patients with GVHD are however less likely to have relapses after going into remission than those without), or they can receive their own stem cells back. However, transplants of their own cells have the risk that some cancer cells might be among the ones transplanted back.
A press release
from the Canadian company Oncolytics Biotech Inc. announces that the company has patented a method of using a common reovirus
to kill the cancer cells in the blood to be transplanted. The virus targets cancer cells with a mutation that has activated the Ras pathway, which occurs in approximately two-thirds of cancer cells. The reovirus’s effectiveness is not exactly new—a study demonstrating it was published in 2003, and the Wikipedia
reports that work was done as long ago as 1998—so the press release is an announcement of the patent. I generally tend to disregard patent announcements because, as in this case, the research has been published by the time the patent is granted, but I think this is worth noting because it sounds as though a therapy may be close to being established. This is probably one of the more common applications of stem cell research in existing medicine, and being able to reduce the re-incidence of cancer would be an important step.
This is not a cure-all, of course, and I can see some immediate areas for follow-up research. More and more research is indicating that cancer is caused by a stem cell gone wrong, which then differentiates and proliferates into cancer cells. Eradicating the cancer cells doesn’t mean that the defective stem cells are gone, and they can keep on pumping out new cancer cells. So a blood transplant would have to eliminate any cancer stem cells as well as actual cancer cells to really eliminate the risk. I’m wondering what sort of work has been done applying viruses to stem cells themselves. Could a therapy be developed that uses a virus to target the stem cells? Would it be more effective as a virus that kills the stem cell or as a virus that carries altered DNA and repairs the mutation? Anybody out there know? I did a quick Google search of stem cell virus and promptly got a lot of articles way over my head—the research required for me to get an answer will take more time than I have for this blog post.