cell that just starts growing essentially out of control. and as a result, it's a type of cancer that also crowds out the other cells so people don't have enough red blood cells, don't have enough white blood cells. that's really the problem. a lot of times what happens in this is that someone may come and develop back pain that. could be the first thing. that's usually because of what you're looking at there on the screen, those sort of punched out lesions is in somebody's skull that. can develop just about anywhere on the body. that's often what takes people to the hospital in the first place. >> debra norville, tom is obviously a news legend in america and you a colleague of his for a long time. no surprise to you or people who know him well he's carried on working as if nothing's happening. he was diagnosed back in august of last summer. what do you think of the way he's responded to this? >> it's typical brokaw. my career wonder have advanced if tom brokaw had not been a