Interesting article:
http://gizmodo.com/5...-against-cancer
"Look close. You may be staring at the end of cancer. Those tiny black dots are nanobots delivering a lethal blow to a cancerous cell, effectively killing it. The first trial on humans has been a success, with no side-effects:
It sneaks in, evades the immune system, delivers the siRNA, and the disassembled components exit out."