I’m just a cell and developmental biologist (whines faintly that cancer is a cell and developmental disease…), but Orac is a real, genuine, bona fide cancer doctor, and he agrees with me that Paul Davies’ atavism theory of cancer is full of crap. He leads you through Robert Weinberg’s authoritative papers on known causes of cancer to show that the idea that cancers are regressions to an ancestral state is nonsense.
I’ll add that I’ve taught a couple of classes on cancer biology and have gone over Weinberg’s The Biology of Cancer, and there’s a lot of developmental biology in there — every time he writes about transcription factors or signaling molecules, it’s all old familiar stuff from fish and fly development. When I see someone like Davies making analogies to evolution, though, I get a sense of deja vu. Once upon a time, people like Haeckel and other natural philosophers looked at how markers (in their case, morphological markers rather than molecules) changed during development and got all excited and claimed that they were recapitulating their evolutionary history. It took someone like Karl Ernst von Baer to come along and say, “You daft wankers, they’re repeating embryological patterns; this is what you see as you develop from the general form to the specific.”
It’s the same story here. Cancer is recycling genes and pathways that are retained because they’re developmentally significant, not because they’re a relic from greatgreatgreatgreat grandma, carefully preserved inside a secret nook in the genome in case we needed to re-adopt a single-celled lifestyle.