Furthermore, we found that CX3CR1 is enriched within the MDP cells of the met-high tumor group (online supplemental figure S3A, B, p=0.041, Wilcoxon rank-sum test), in line with a previous study demonstrating that MDPs are initially identified as CX3CR1+ cells.26 In addition, the transcription factor IRF2BP2, which has been reported to regulate macrophage activity,27 was also upregulated in MDPs from met-high tumors compared with MDPs from met-low tumors. This evidence concerns the gene CX3CR1 and neoplasm.