Ornithine decarboxylase (ODC) initiates the polyamine biosynthetic pathway. The amount of
ODC is altered in response to many growth factors, oncogenes, and tumor promoters and to
changes in polyamine levels. Susceptibility to tumor development is increased in transgenic
mice expressing high levels of ODC and is decreased in mice with reduced ODC due to loss
of one ODC allele or elevated expression of antizyme, a protein that stimulates ODC
degradation. This review describes key factors that contribute to the regulation of ODC …