The amplitude and duration of epidermal growth factor receptor (EGFR) signaling to Ras and its downstream target MAP kinase (MAPK) affect the fate of the cell; EGF stimulation of rat adrenal pheochromocytoma (PC-12) cells results in transient Ras activation and proliferation whereas nerve growth factor (NGF) stimulation leads to consistent activation of Ras-MAPK, exiting mitosis, and differentiation57,58. This evidence concerns the gene EGF and adrenal gland pheochromocytoma.