Tumors

On Respectful Insolence, Orac examines the dangers posed by experimental stem cell treatments, which are often offered outside the United States in order to avoid regulatory oversight. Orac writes that stem cell therapy is "moving from cutting edge science to applied science" but treatments are not yet refined to the point of being safe and effective. In the case of Jim Gass, a stroke patient who sought stem cell therapy at clinics around the world, the intervention proved to be disastrous, as cells injected into his lower back grew into a cancer-like mass that left him paralyzed from the…

In a phenomenon known as Peto's paradox, large mammals do not develop cancer more often than small mammals, despite having more cells that could go haywire. On Life Lines, Dr. Dolittle writes "Some researchers suggested that perhaps smaller animals developed more oxidative stress as a result of having higher metabolisms. Others proposed that perhaps larger animals have more genes that suppress tumors." But a new hypothesis argues that large mammals have evolved to minimize the activity of ERVs, which are ancient viral elements integrated into our DNA. Active ERVs can cause cancer and possibly…