Right. This is the exact type of language I found everywhere else. Just because it "can" mutate which "can" become cancerous does not mean there is a direct correlation between UV radiation and skin cancer. I'd like to see some actual studies with controlled variables.
Getting cancer is like winning the lottery, and every time you go out in the sun, use a cleaning product, get an X-Ray, take an intercontinental flight, eat a banana, etc. you get a varying number of tickets. Unlike a lottery, once you finally "win" it's virtually impossible to figure out which ticket was "lucky".
To do a controlled study on humans you'd need those humans to record an impractical amount of information about their day-to-day actions over their entire lives. This isn't going to happen anytime soon. To make matters worse, humans also use sunlight to synthesize Vitamin D, and low levels of Vitamin D are also correlated with cancer. So... Too much UV gives you cancer and too little can give you cancer if you don't get enough Vitamin D in your diet, which might also give you cancer. Okay... So use mice. Do mice respond exactly the same way to everything as humans? No... Probably not...
Medical science is a bit like trying to figure out how to build the ultimate F1 car on a budget that only lets you work with Lada's.
One nice natural experiment is drivers. People who drive in the US get more sun on the left side of their face and their left arm. People who drive in Australia get more sun on the right side of their face and their right arm. If you measure which side people tend to get cancer on it seems to track this.
