Abstract: The present invention provides a method to increase the production of a regulatory molecule, i.e., a molecule that regulates cell behavior, such as a cytokine or a protooncogene, in a population of transfected cells, whether normal (resting or activated) or tumor cells. The method involves mutating a native or "wild type" cDNA sequence that encodes an mRNA sequence for a regulatory molecule to form a mutant cDNA sequence capable of producing a more stable mRNA sequence.