RUNX2 and breast cancer: Consistently, the MCF7 and T47D cells that stably express ectopic RUNX2 down-regulated RUNX1 levels compared to the Empty controls (Figure 7B), which was also observed in the RUNX1 mRNA levels (Figure 7C, 2nd and 4th graphs), indicating RUNX1 and RUNX2 could cross-regulate each other in BC cells [56].