Very common press release/headline meme: the question in the title of the article is literally never answered (or the opposite of the headline's claim is true). This research plainly DOES NOT explain why certain mice got cancer and others didn't, let alone why smoking/UV rays cause cancer in some humans but not others. There was no control group for exposed mice that would've allowed them to look at which biological differences made one group get tumors and the others not (the study doesn't appear to actually be interested in that question).

The language here is also pretty hyperbolic. We've known for decades that certain gene mutations cause increased cancer risk in the context of a certain genetic background (BRCA1/2, etc.). Using language like "for the first time" is just juvenile, or purposeful lying at worst.