CX3CL1 and cancer: The CX3CR1/CX3CL1 and CXCR3/CXCL10 axes have been demonstrated to be involved in the proliferation, survival, and metastasis of various malignant tumor types, including breast cancer, and were suggested to predict the site of metastatic relapse (Andre et al., 2006; Zhu et al., 2015).