I don't think many people who suffer(ed) chronic street will need to see the hard research on humans to confirm it affects your health in a negative way.
That’s pretty different from what the headline is contending, though… Your statement is certainly true, of course, but the article is specifically claiming a link to cancer.
How are you certain? Chronic stress can be really harmful, but saying that it spreads cancer is a stretch that needs to be scientifically proven. Making mice artificially stressed isn't the way though.