Cell phones work on microwaves which are non ionoising.
You would not have expected any effect other than heating.
They have not been around long enough for long term effects to show up, but researchers have found unexpectedly high correlations, mainly for brain cancers.
As has been said, the mechanism by which this could be caused is not clear, and the biggest risk will be from the handset not the mast.
UK government advises that children do not use them (thinner skull, developing brain).
The advice is universally ignored.