Theresa,
I also have Izzo and Santillo in my family tree. My paternal line is Martino, and there are both Izzo's and Santillo's. My dad's maternal line(Zona) includes Izzo's. Interestingly, his paternal line also includes Zona's! Confusing for me at the start, but am now sorting everything out.
When I first realized a couple of years ago, that I could actually find out about my Italian ancestors- all of whom came from Petrulo, or close by, my dad kept mentioning a Cipro. I have not been able to find any link yet, but am hoping to.
I have not been able to find out anything much earlier than mid 1800's.
We are close by each other, I live in North Rose!