PROX1 and breast cancer: Thus, we investigated whether BCs could serve as a source of Prox1 for MG by genetically eliminating the Prox1 gene and expressing EGFP complementarily in BCs of Prox1fg/fg;Chx10-CreERT2 mice, which express CreERT2 predominantly in the BC population in a Tam-dependent manner30,42 (Fig. 3b).