Just for the fun of it, and because I've been reading studies like my previous post, I looked to see how much casein is in typical dairy foods.
Modification of Bovine β-Casein to Improve the Characteristics and Manufacturing Properties of Cow's Milk
The site above says that there are about 27.3 grams of casein in 1 liter of whole cow's milk. (The substance of that article is a little disturbing, but I was just browsing for casein content.) From that ...
Approximate! Casein Amounts:
6.5 g casein in 1 cup whole milk
5.7 g casein in 1 oz. cheddar cheese
11.3 g casein in 1 cup plain fat-free yogurt
Skim milk, low-fat cheese, and dryer cheese would provide more casein.
Approximate Protein Amounts:
3 oz. beef tenderloin - 24 g protein
3 oz. of cheese - 21 g protein
1 cup plain non-fat yogurt - 14 g protein
A half-cup cubed chicken breast - 22 g protein
3 oz white tuna - 20 g protein
Protein In Diet:
Low protein* (4.35%) of a 2000 calorie diet = 22 grams protein
High protein* (17.4 %) of a 2000 calorie diet = 87 grams protein
(Average US protein intake (15.4%) of a 2000 calorie diet = 77 grams protein)
The study in my previous post, taken in isolation, cannot inform on which component in casein affected liver tumor growth.
If it was the protein, and for whatever reason you're of a mind to apply the finding, you'd be limiting your total protein to ~22 g/day (assuming a 2000 calorie diet). (Plant-sourced protein may behave differently. This study did not elucidate.)
If it was the casein, you'd be limiting total casein intake to ~25 g/day (assuming a 2000 calorie diet).
* As defined by the previous study.