Cancer and associated cells in the cancer microenvironment may release a variety of pain mediators, including adenosine triphosphate, bradykinin, cytokines, chemokines, nerve growth factor, prostaglandins, and several vascular factors, including such as endothelin 1 and vascular endothelial growth factor to either excite or sensitize nociceptive primary afferents. Here, NGF is linked to cancer.