In 2015 my (now ex) girlfriend was diagnosed with TNBC. I obviously researched the hell out of it to gain as much of an understanding as I possibly could as a non-medical professional as I'm sure anyone would, and most of my reading suggested that it was mostly African American women and youngish white ladies who tend to get this.
As far as I know, she had used permanent die at least once in her early twenties. Thankfully less than a year later and after chemo and surgery, she fully recovered.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7783321/
Edit: added space after comma, fixed grammo