The abnormal expression of NGF/NGFRs may alter cell death and survival, cell proliferation, invasion and metastasis in various cancer cells depending on cell types, the receptor types, the expression levels of receptors or adaptor proteins via activation and regulation of a variety of signaling pathways, such as NF-κB, PI3K/Akt, Ras/MAPK, and so forth [27–31]. Here, NGF is linked to cancer.