In addition, recent studies have shown that cancer cells outside the CNS can promote axonogenesis by expressing and releasing nerve growth factor, neurotrophic factor, or ephrin B1 (an axon-guidance molecules); they can also recruit new nerve fibers and increase the innervation of the local tumor microenvironment (Ayala et al., 2008; Hayakawa et al., 2017). The gene discussed is NGF; the disease is neoplasm.