Research studies have found many factors which lead to the formation of cancer. A couple of studies that repeatedly showed that eating meat fat is a cause of cancer :
* A 12-year research study, of more than 5,000 vegetarians and over 6,000 meat eaters found that vegetarian diets reduce risk of death from all causes, including cancer. People who ate no meat had a 40% lower risk of dying from cancer and a 20% lower risk than meat eaters dying from a cause. (Research is co-authored by Margaret Thorogood, Ph. D.)
* A Harvard study of nearly 48,000 men, aged 40-75 , found that meat fat helps tumors grow more quickly. leading sources of saturated fats are beef, pork, processed meats, whole milk, dairy products, and fats and oils ( such as butter, margarine, and mayonnaise).
* Another Harvard study has found that even eating red meat (with much less fat content) was also dangerous. A 6-year study of nearly 90,000 women found that those who ate red meat as a main dish each day were 21/2 times more likely to have colon cancer than those who seldom, or never, ate meat. Other studies revealed that frequent consumption of meat is also associated with an increased risk of breast cancer, according to Harvard School of Public Health.

This studies is very good.