

Something about radiation
All known cancer-inducing agents — certain chemicals and viruses and ionizing
radiation — act by breaking chemical bonds to produce DNA mutations.
Ionizing radiation refers to gamma rays, x-rays, most ultraviolet light
and certain subatomic particles. Their energy is high enough to detach
an electron from an atom.
Lower-energy, non-ionizing radiation from light bulbs and cell phones (both part of the electromagnetic spectrum)
can't do damage unless there's enough focus to heat tissue. Even if
cell phones could deposit harmful heat, circulating blood should
dissipate this.
Still, there's something unsettling about bathing your brain in
supposedly innocuous radio waves. So scientists are investigating non-ionizing, non-thermal or weakly thermal effects of radio waves. The theories get sketchy here, though.
One could argue that the cornea can't dissipate heat as well as
other body parts; animal studies have found a link between microwaves
and cataracts. But most of us generally put the cell phone to our ear,
not eyes.
Also, humans might have thermoreceptors, like thylakoids inside
plants enabling photosynthesis, that permit radio waves to trigger a
cascade of chemical events. What this could mean for human health is
anyone's guess; this is just a plausible mechanism should human studies reveal a link between cell phone use and cancer.
But studies don't reveal a cancer link.