STAT3 and cancer: In concordance with our previous studies in non-IBC triple-negative BC (TNBC) (27), C/EBPδ supported in vitro invasiveness, expression of prooncogenic factors (CXCR4, STAT3 and Notch pathway activation), and cancer stem cell markers (CD44+/CD24–) in SUM149 and IBC-3 cell lines, and it supported growth of established SUM149 experimental metastases in vivo (Supplemental Figure 1, A–G; supplemental material available online with this article; https://doi.org/10.1172/jci.insight.156057DS1).