NGF and prostate cancer: NGF survival signaling through the TrkA pathway follows three main routes of intracellular second messengers: 1) Src homology 2 domain containing (Shc)/PI3K/AKT leading to survival of breast and prostate cancers, 2) the Ras/MAPK induced proliferation and invasion in breast and prostate cancer, and cell death by autophagy in medulloblastoma and glioblastoma, 3) PLC-γ/PKC signaling involved in metastasis [36].