INS and type 2 diabetes mellitus: Here, we propose that, as for any drug, there is a dose range for biguanides that is without any effect, one corresponding to “diabetobiguanides” with a pharmacological effect (e.g., insulin sensitization in type 2 diabetes, prevention of insulin-dependent carcinogenesis, indirect inhibition of insulin and growth factor-dependent cancer growth) but with minimal toxicity and another corresponding to “oncobiguanides” with pharmacological (i.e., direct and strong anticancer activity against cancer cells) as well as toxic effects.