IGF1 and neoplasm: The tumor progression program triggered by CXCL1 in BCSCs also includes the expression of inflammatory mediators, proteases and growth factors, specifically, IL1β, CCL18, CSF2, MMP14, HGF, and IGF1. IL1β is involved in multiple aspects of tumor initiation and progression, and has shown to promote metastatic colonization of BCSCs to the bone (Mantovani et al., 2018; Eyre et al., 2019).