RUNX1 and breast cancer: Interestingly, Recouvreux et al. have recently demonstrated a physical interaction between the tumor suppressor Foxp3 and RUNX1 that suppresses the trans-activating properties of RUNX1 and suggested that any disruption in this equilibrium in favor of RUNX1 (which is viewed as a tumor enhancer based on their results) may contribute to breast cancer development [48].