NGF and neuroblastoma: Finally, although retinoic acid-induced neurite outgrowth is unaffected by abrogation of cellular ganglioside synthesis in LAN-5 cells grown in a serum-supplemented environment (Li and Ladisch, 1997), reduction of cellular ganglioside synthesis is associated with decreased NGF-induced outgrowth of neuritic processes in a NB cell line grown in serum-free medium, and is reversible by exogenous addition of gangliosides (Rosner, 1998).