NGF and neuroblastoma: Its discovery dates back to 1984 as a 57 kDa Triton X-100-insoluble protein observed in mouse neuroblastoma cell lines and the rat pheochromocytoma PC12 cell line, and, in these cells, 35S-methionine incorporation into this protein was enhanced following nerve growth factor (NGF) treatment indicating a regulation from this neurotrophin [18].