CX3CR1 and neoplasm: CX3CL1’s unique receptor CX3CR1 is expressed by a wide variety of immune cells and tumor cells in malignancies such as multiple myeloma, metastatic pancreatic cancer, prostate cancer and lymphocytic leukemia (Nishimura et al., 2002; Nakayama et al., 2010; Corcione et al., 2012; Huang et al., 2012; Wada et al., 2015; Liu et al., 2018).