The nickel sized basal cell carcinoma that was cut out of my face was approximately the center of the cell phone I used for a couple of hours a day, and on the same side I held the phone. I use the phone on speaker for any long call, or keep it brief, now.
I can't say that was necessarily the cause of the cancer, but I'm not taking any more chances. One long scar down the side of my face is (hopefully) enough.