A fellow chick here, with over 10 separate spots of basal cell removed in the last 15 years.
First couple removed in my mid 20's. From areas that NEVER saw the sun. The doc wanted to ignore them until I demanded one be removed because it sat right under the underwire in my bra, irritating the heck out of that spot. Once biopsied, it came back basal cell and suddenly I had about 5 more spots removed on my stomach. Eventually, more removed on my neck and shoulders - places that have seen lots of sun exposure.
Few years ago I got what appeared to by a sty on my lower left eyelid. Went to the doc repeatedly over the course of about 18 months and each time they wrote it off to being a persistent sty. I've had many a sty before, and I knew it was NOT. At the Wolf Clinic a doc made an offhand comment that if I was older or had a history of skin cancer, then they'd biopsy. When I told him about my history, a biopsy was done on the spot. In 2010 I had a Mohs procedure done by Dr. Bean and reconstruction (4 x 8 mm square take off my lower lid) at Wolf with Dr Cassidy. Looks awesome today.
Turns out wearing a pirate patch for awhile is not near as fun as you might think...

frown:
From my experience basal cell is both sun exposure and genetics. You watch for spots. If they grow or change, go to the doctor. PM me if you your wife wants to talk about anything. I've run this race many times before and can talk her off the ledge.