NGF and malignant colon neoplasm: Moreover, their impact in the receptor tyrosine kinase signaling (e.g., EGFR, IGFR, VEGF, or nerve growth factor (NGF) receptors) warrants further investigations, because of the role of these receptors and their intersection with the so-called nuclear receptors in many human proliferative diseases, including breast, prostate, and colon cancers [206,207,208,209,210,211].