Four cups is a lot of coffee, that’s a lot of caffien and stress on the heart, my guess is 4+ cups also has it’s downside, that’s why these kinds of studies are stupid
No one in my extended family has ever gotten cancer. Very heavy coffee drinkers. My father, his father, and all of his 8 siblings died in their 60’s and very early 70’s of heart attacks though, before they could get cancer.