This is a little fuzzy. It's likely that most organisms of a meaningful size have _some_ number of cancerous cells, so I'm not sure that distinction is as crisp as your phrasing. As for cancer risk, there is some reason to believe a connection, but as with most complex medical questions, there is only so much certainty, even in large studies, until we understand detailed mechanisms.

http://www.thelancet.com/journals/lancet/article/PIIS0140-67... https://www.jstage.jst.go.jp/article/endocrj/52/5/52_5_571/_...