TheCX3CL1/C-X3-C motif chemokine receptor 1 (CX3CR1), which is overexpressed in PC tissues with spinal metastasis, appears to promote cell migration by activating the Src/Fak pathway, as inhibitors of these kinases suppressed the cell migration induced by CX3CL1 or CX3CR1 overexpression [39]. Here, PTK2 is linked to pachyonychia congenita.