Big Brain is Why Humans Get Cancer

That
big brain of ours? Yeah, the one that you’re using to read this Neatorama
post. It’s also the reason us humans get cancer.

That’s what Georgia Institute of Technology researcher John McDonald
discovered when comparing our cells with those of other primates:

When cells become damaged or just aren't needed, they self-destruct
in a process called apoptosis. In developing organisms, apoptosis is
just as important as cell growth for generating organs and appendages
– it helps "prune" structures to their final form. […]

McDonald compared skin cells from humans, chimpanzees and macaques
and found that, compared to cells from other primates, our cells are
reluctant to undergo apoptosis. When exposed to apoptosis-triggering
chemicals, human cells responded significantly less than the chimp and
macaque cells. […]

McDonald suggests that humans’ reduced capacity for apoptosis could
help explain why our brains are so much bigger, relative to body size,
than those of chimpanzees and other animals. When a baby animal starts
developing, it quickly grows a great many neurons, and then trims some
of them back. Beyond a certain point, no new brain cells are created.

Human fetuses may prune less than other animals, allowing their brains
to swell.

The downside to this is that we’re more susceptible to developing cancer
cells, which do not respond to apoptotic signals: Link