RB1 and breast cancer: In order to understand the mechanisms that underpin BRIP1‐promoted BC cell proliferation, our results revealed that siRNA BRIP1 suppression, arrested cell cycle at the G1/S phase, and TaqMan array identified several key cell cycle regulators that were down‐regulated upon BRIP1 inhibition, including c‐Myc (−3.7), Ras GTPase (−3.8) and Rb (−4.8) accompanied by cell cycle arrest at G1.37