Linda and brother Richard
I don’t get it. I
have been studying biology, especially cancer biology, for over five years
now. Admittedly, I started from an unmatched
level of ignorance, never having had a formal course in biology, either in high
school or in college. Still, I did pay
close attention to the Teaching Company’s excellent course on general biology –
I went through it three times – and, as a geologist, I had to know a little about evolution. And, of course, I have
struggled through many hundreds, maybe a thousand or more, articles on cancer
biology. Notwithstanding, I still don’t
get it.
What I don’t get is why cancers thrive. The evolutionary model seems to tell us that
biological changes occur because favorable random mutations increase the
likelihood that a creature will survive and reproduce. Cancers, however, may “reproduce”
(metastasize) , but they always die – and their “offspring” with them. They don’t pass on survival tactics to other
cancers. How, then, do the "evolve" tricks
to deceive or combat the immune system, or sucker surrounding tissue into
permitting them to acquire the blood supply they need for growth? Time after time I have run on passages that suggest
to me that a particular type of cancer is sentient, at least insofar as
devising clever ways to grow and prosper.
Such nastiness can’t evolve, but there it is. Like I said, I just don’t get it.
Maybe there is a Devil, after all.
Well, maybe I do get it. Whenever mitosis occurs, errors are made. We have evolved a complicated set of processes to find and correct those errors, by good, honest Darwinian means, but inevitably, some slip through. Say one such error disables a tumor-suppressor gene – needed to prevent the cell within which it occurs from reproducing without limit (going “cancerous”). So a small cancer appears. But what tells that little rascal how to protect itself from the immune system, recruit new blood vessels, metastasize? Is it possible that other mutations are needed? Could it be that most potentially deleterious mutations come to naught because they fall on uncultivated ground, so to speak? Could it be that I’m just blathering about something I know nothing about? Or have I reinvented the wheel but described it differently? And why are you still reading this stuff, anyway.
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