There is not much difference in "cancer correlation with plant proteins" and "cancer correlation with animal proteins".
High cholesterol is correlated with some cancers. But areas with high cholesterol are riddled with other risk factors. Campbell does not mention that.
Breast cancer is correlated significantly with sugar, alcohol and industry hazards. The association with animal fats is not statistically significant. Campbell does not mention that.
Areas with high animal food intake are not correlated with higher cancer rates at all.
Schistosomiasis is a profoundly strong risk factor for developing colon cancer and rectal cancer. It also happens that cholesterol also correlates with schistosomiasis infection. In regions with close to zero schistosomiasis infection there is no positive correlation between cancer and cholesterol.
Leukemia correlates strongly with working in industry. In the counties where few people work in industry, no correlation exists between cholesterol and leukemia. Cholesterol is actually slightly protective against leukemia.

The mortality rates for near-vegan and higher-animal-foods groups are quite similar, with the animal food group coming out more favorably in some cases (death from all cancers, myocardial infarction, brain and neurological diseases, lymphoma, cervix cancer). This little comparison might not carry a lot of scientific clout due to its small sample size, but it does blatantly undermine Campbell’s assessment.

Why does Campbell indict animal foods in cardiovascular disease (correlation of +1 for animal protein and -11 for fish protein), yet fail to mention that wheat flour has a correlation of +67 with heart attacks and coronary heart disease, and plant protein correlates at +25 with these conditions?

Why does Campbell overlook the unique Tuoli peoples documented in the China Study, who eat twice as much animal protein as the average American (including two pounds of casein-filled dairy per day)—yet don’t exhibit higher rates of any diseases Campbell ascribes to animal foods?

Why does Campbell point out the relationship between cholesterol and colorectal cancer (+33) but not mention the much higher relationship between sea vegetables and colorectal cancer (+76)?

Why does Campbell fail to mention that plant protein intake correlates positively with many of the “Western diseases” he blames cholesterol for—including +19 for colorectal cancers, +12 for cervix cancer, +15 for leukemia, +25 for myocardial infarction and coronary heart disease, +12 for diabetes, +1 for breast cancer, and +10 for stomach cancer?

Campbell demonstrated that casein promotes cancer in rats. He did not demonstrate that:
- The casein-cancer mechanism behaves the same way in humans as in lab rats.
- Casein promotes cancer not just when isolated, but also when occurring in its natural food form
- There are no differences between casein and other types of animal protein that could impose different effects on cancer growth/tumorigenesis.

Results of another Campbells study:

20% menhaden oil diet, rich in omega 3 fatty acids, produced a significant decrease in the development of both the size and number of preneoplastic lesions when compared to a 20% corn oil diet rich in omega 6 fatty acids. This study provides evidence that fish oils, rich in omega 3 fatty acids, may have potential as inhibitory agents in cancer development.

Why does Campbell avoid mentioning anything potentially positive about animal products in “The China Study,” including evidence unearthed by his own research?

In sum, “The China Study” is a compelling collection of carefully chosen data. Unfortunately for both health seekers and the scientific community, Campbell appears to exclude relevant information when it indicts plant foods as causative of disease, or when it shows potential benefits for animal products. This presents readers with a strongly misleading interpretation of the original China Study data, as well as a slanted perspective of nutritional research from other arenas (including some that Campbell himself conducted).