NGF and sarcoma: During a research endeavor exploring the specific growth-stimulating impacts of mouse sarcoma on the sensory and sympathetic nervous systems of chick embryos, it was unveiled that mouse sarcoma had the ability to generate a specific factor to specifically promote the growth and development of nerve cells.30 Later, this factor is well-known as nerve growth factor (NGF) and stands as the inaugural growth factor to be discovered, unveiling the pivotal role of extracellular factors in modulating cell growth and differentiation.