BDNF and cancer: Our findings that NGFR can directly and indirectly suppress p53 activity were unexpected, as NGFR was originally found to be a transmembrane pan-receptor involved in the initiation, development, and maintenance of the nervous system and human cancers (Lee et al., 2001; Molloy et al., 2011; Patapoutian and Reichardt, 2001), which binds with low affinity to all mature neurotrophins, including nerve growth factor (NGF), brain-derived neutrophic factor (BDGF), neurotrophin 3 (NT-3), and neurotrophin 4/5 (NT-4/5), as well as their precursors, pro-neurotrophins, with high affinity (Barker, 2004).