" Foci are precursor clusters of cells that grow into tumors. Although most foci do not become full-blown tumor cells, they are predictive of tumor development. By watching foci develop and measuring how many there are and how big they become,32 we could learn indirectly how tumors also develop and what effect protein might have. By studying the effects of protein on the promotion of foci instead of tumors, we could avoid spending a lifetime and a few million dollars working in the lab. What we found was truly remarkable. Foci development was almost entirely dependent on how much protein was consumed, regardless of how much aflatoxin was consumed! "

― T. Colin Campbell , The China Study: The Most Comprehensive Study of Nutrition Ever Conducted and the Startling Implications for Diet, Weight Loss, and Long-term Health