CXCL1 and breast cancer: Our study adds a new piece to the puzzle of the BC microenvironment (Figure 4), by revealing that BCSCs can be a prominent source of CXCL1, particularly in TNBC, which is enriched in CSCs (Honeth et al., 2008; Ma et al., 2014) and more frequently expresses CXCL1mRNA, as evidenced by bioinformatic analyses of data obtained from the PanCancer database (Berger et al., 2018).