Discover gives a brief introduction to cancer immunity in mice: "Cui bred the mouse and found that 40 percent of its offspring share a remarkable resistance to many forms of cancer. When the animals' immune systems identify a cancer cell, a genetic tweak allows their bodies to launch a massive attack of white blood cells that kills the budding tumor. ... When they inject white blood cells from any of these anticancer mice into their nonresistant brethren, the injected animals become resistant as well, fighting off induced cancer in a matter of weeks or avoiding it entirely. ... Cui has sampled a group of human volunteers and found that 10 to 15 percent have similar super cancer-fighting white blood cells. That could explain why some people never get cancer and why others' tumors spontaneously regress. Cui proposes injecting these people's white blood cells into cancer patients to see if he can transfer their immunity."