Direct mechanisms include 1) phosphotyrosine phosphatase activation, 2) tyrosine kinase inhibition, 3) cell cycle arrest by downregulation of phosphorylation and activation of the rat sarcoma virus/MAPK pathway, 4) apoptosis of cancer cells by intracellular acidification and endonuclease activation, and 5) inhibition of GH and cytokines by inhibition of cyclic adenosine monophosphate and calcium production. This evidence concerns the gene GH1 and cancer.