The China Study is supposed to have taken a more comprehensive view. I've not read any criticism of it (which is why I asked for some). But he cites more than one study that demonstrated the ability to "turn on and off" cancer growth in rats exposed to a particular carcinogen by raising and lowering their animal protein intake. That seems like pretty damning evidence against that particular protein.

(Edit: Assuming of course, said studies are accurately being described to me. I haven't read the actual data.)