Cancer is a metabolic deficiency.

Cancer is regarded here as a metabolic deficiency originating in stem cell destruction. Tissue stem cells are postulated to secrete a vital substance 'A' necessary for proper tissue function. Carcinogens interfere with 'A' production mainly by destroying stem cells which the organism is incapable of fully replenishing so that less 'A' is produced. This irreversible 'A' deficiency may be compensated by a substitute, or substance 'B', produced by a specialized organ, the neoplasm. Since carcinogens continue depleting more and more stem cells, the deficiency worsens. In order to meet the increasing demand, the neoplasm proliferates more and more until reaching a stage of decompensation when the harm inflicted by it outweighs its benefit. Stem cell depletion is regarded here as the final common pathway for carcinogen action. The theory predicts that following a supply of 'A' producing stem cells or inactivated 'B' producing neoplastic stem cells, the tumor will regress.