Cancell/Cantron/Protocel was developed in the 1950s by a chemist who called it Entelev and provided it free of charge to patients with terminal cancer. Reviewed in [1,2] In 1984, production was taken over by a second manufacturer who distributed the mixture free of charge under the trademarked name Cancell to individuals with cancer, AIDS, and other conditions. Reviewed in [1,2]
The two principal manufacturers of Cancell/Cantron/Protocel have offered somewhat different explanations for cancer development, but their theories about how the mixture works are quite similar. According to the original manufacturer, human cells can be normal, cancerous, or primitive. Each of these cellular forms is distinguished by the degree of oxygen utilization in cellular metabolism. Normal cells use aerobic metabolism (glycolysis plus additional biochemical reactions that require oxygen) to produce the energy needed for growth and maintenance. Primitive cells only use glycolysis, which is a much less efficient way to produce energy. It was proposed that normal cells become cancerous when, in response to certain damaging conditions such as chronic energy stress (a demand for energy greater than the cell's ability to produce it), they reach a critical point and begin to rely mainly on glycolysis to produce energy. According to this theory, cancerous cells still maintain many of the features of normal cells and cannot be recognized by the body as foreign. According to the original manufacturer, Cancell/Cantron/Protocel causes cancer cells to become completely primitive, i.e., their residual aerobic metabolism is inhibited and they produce energy solely by glycolysis. The resulting primitive cells are then seen by the body as foreign and destroyed. While the aerobic metabolism of normal cells is also inhibited by Cancell/Cantron/Protocel, they are too far removed from the critical point to become cancerous or completely primitive. Reviewed in 
The Gonzalez regimen, developed by Dr. Nicholas Gonzalez, involves taking pancreatic enzymes thought to have anticancer activity. The regimen also includes prescribed diets, nutritional supplements, and coffee enemas (see Question 1).
The Gonzalez regimen is based on the theory that pancreatic enzymes help the body get rid of toxins (harmful substances) that lead to cancer (see Question 3).
A few studies have examined the effect of pancreatic enzymes in animals with implanted cancers, but...
The second manufacturer suggested that a bacterium called Progenitor cryptocides is involved in cancer development. Reviewed in  According to this theory, P. cryptocides becomes activated in individuals whose bodies are damaged by an improper diet. Once activated, this bacterium helps cause damaged normal cells to shift their energy production from aerobic metabolism to glycolysis. When the demand for energy exceeds the damaged normal cell's ability to produce it, the cell mutates and becomes cancerous. Once again, Cancell/Cantron/Protocel forces cancerous cells into a completely primitive state where they self-digest and are replaced by normal cells. The waste material produced by this self-digestion process is discarded by the body in a variety of ways: in urine, stool, vaginal discharge, or perspiration; it may also be vomited or coughed up. Reviewed in