In the New Warriors, Angelica was worried her radiation powers might cause her problems with cancer and/or her fertility.
When she joined the Avengers, Hank Pym noted that her body had a natural resistance to microwave radiation, but it was developing more slowly than her power blasts were, so he designed an undersuit which would regulate her bodies ability to process radiation until it had caught up naturally. It was viewed as being a temporary step until she was fully grown.
Of course, none of that means she couldn't develop cancer through other, perfectly natural, means. Just that it wouldn't be caused by microwave exposure. Of course, that might be the point, radiotherapy probably won't work on her since she's immune.
Shades of Diamond Lil in Alpha Flight, who was diagnosed with cancer, but her own invulnerability to just about anything meant she couldn't be treated by any normal means.