EGR2 and breast cancer: This heterogeneity in the embryonic origin of BC cells is likely to explain another observation: whereas targeted ablation of NC-derived cells expressing Egr2, obtained by combining Wnt1Cre and Egr2GFP/DT alleles, is effective, but not lethal before birth (Odelin et al., 2018), targeted ablation of all Egr2-expressing cells does lead to embryonic death at around E15.5 (this study).