CX3CL1 and breast cancer: The membrane-bound form enhances cell adhesion, while soluble CX3CL1 has the function of chemotaxis towards cells expressing CX3CR1. CX3CL1 is the only member of the CX3C chemokine subfamily and has been shown to have anti-cancer effects in other tumors such as colon cancer (Hughes and Nibbs, 2018), breast cancer (Kadomoto et al., 2020), and cervical cancer (Khare et al., 2021).