LEF1 and cancer: Building upon our reporting of the previously uncharacterized strategy of O'PROTACs to destruct generally “undruggable” transcription factors in bioRxiv,[19] in the current communication we systematically present the procedures of design and synthesis of LEF1 and ERG O'PROTACs, the mechanisms of action, and their anti‐cancer efficacy in vitro and in vivo.