Other neurotrophic factors such as brain-derived neurotrophic factor (BDNF) and glial cell-derived neurotrophic factor (GDNF), have been shown to induce tumor migration via upregulation of VEGF and activation of p38 and PI3K/Akt signaling pathway (Huang et al., 2014; Huang et al., 2015). Here, GDNF is linked to neoplasm.