In contrast, macrophages in glioma TME with CX3CR1 expression were differentiated from CX3CR1lo peripheral monocytes entered the cranial cavity (Quail and Joyce, 2017), which highly express CD45 and CCR2 (Hambardzumyan et al., 2016; Chen Z. et al., 2017). Here, CX3CR1 is linked to central nervous system cancer.