The development of cancer depends on an interplay of genetic factors and the environment. Environmental carcinogens can cause a build up in cancer-causing mutations. As well as that, environmental factors can cause existing harmful genes to be turned on and express oncogenic proteins.
Also, cancer cells thrive in an acidic environment. Thus, by limiting alcohol, eating mostly plant based foods, and maintaining a natural body weight one can reduce risk of cancer. All foods of animal origin contain steroid hormones (i.e. estrogen).
Hormones in dairy products and other growth factors could stimulate the production of hormone-sensitive tumors. Most animal products have IGFA.
Breast, prostate, and colorectal cancers have been on a rise in the last twenty years. This is largely due to increased exposure to environmental felons like BPA in plastic and EMF radiation from cellular devices.