Fig. 8

A schematic summary of the hypothesis. a The pancreas secretes chymotrypsin (yellow) as a digestive enzyme in proportion to the amount of food (protein) consumed. Most passes through the gastro-intestinal (GI) tract unchanged. Subtilisin present in processed foods as well as Bacillus subtilis present in soil, livestock feed and probiotics, enter the gastro-intestinal tract orally, while subtilisin present in cleaning products may access the body via the respiratory system or dermal contact. Both proteases will be in contact with cells in the intestinal epithelium and some will be absorbed into the cardiovascular circulation from where both will access all organs and tissues, promoting oncogenesis. b At the cellular level netrin promotes cell stability and proliferation, with DCC acting to inhibit that activity. The unhindered activity of DCC induces cell death, partly by apoptosis. When DCC is removed by subtilisin or chymotrypsin, netrin can promote proliferation leading potentially to cancer