IMP3, also known as Insulin like growth factor 2 mRNA binding protein 3, is an oncofetal protein that stabilizes IGF-II mRNA for trafficking and plays an important role in cell growth and migration. Expression is normally found in developing tissues during early embryogenesis in a variety of fetal tissues including the liver, lung kidney, thymus, and placenta. Only low or no level is found in normal adult tissues. IMP3 has been found in various malignant tumors of the lung, gastrointestinal tract, liver, endometrium, and bladder. It may play a role in tumor proliferation, invasion and metastasis.