"In efforts to educate the body to fight off cancer, researchers have found that some immune cells are "smarter" than others. Working with collections of human cells, Johns Hopkins Kimmel Cancer Center scientists tested kill-rates of two kinds of T-cells "primed" to home in on myeloma, a cancer of the bone marrow. Those that live in the bone marrow outperformed their counterparts circulating in the blood by more than 90 percent..."
Science Blog
http://www.scienceblog.com/cms/node/7109