The first growth factor, nerve growth factor was discovered by Stanley Cohen and Rita Levi-Montalcini in 1952. The assumption of a soluble, diffusible agent exist in embryo or sarcoma was made based an interesting phenomenon discovered in the laboratories of Prof. Viktor Hamburger and Rita Levi-Montalcini more than half a century ago. Researchers found that the transplantion of an extra limb bud to chick embryo would induce the growth of new nerve fibers on the periphery of the transplanted limb; furthermore, the graft of mouse sarcoma 180 on to the body wall of chick embryo would leads to the penetration of sensory nerve fibers in the sarcoma. Based on making extract from the sarcoma, nerve growth factor was discovered. Because of its heat-labile, non-dialyzable, protease-sentitive and DNase- or RNase-insentitive characteristics, the growth factor was believed to be a protein.
Then, another nerve growth factor was purified from snake venom in 1959, and the first epidermal growth factor was isolated from the submaxillary gland of the mouse in 1962. Nowadays, many growth factors have been reported, and their number is still expanding. The discovery of nerve growth factor (NGF) opened up a huge new area of cell biology, and won the Nobel Prize in 1986.