I was diagnosed in 2005 with SCC of the right lateral tongue. I also had no risk factors. I did a lot of research, asked a lot of questions, and even submitted some of my “cells” for a study looking into a genetic connection and another study (but don’t recall specifics). Over the years I meet many women (in person and on-line) who also had no risk factors and based on the people I meet I think the 5-7% of “no know cause” is on the low side. I did have a cell phone in 2005, but at that time it was not my primary communication method. My doctors suggested irritation from a sharp tooth rubbing my tongue, but I didnt have any sharp edges on the teeth in that area.