NUMB and neoplasm: Study shows that chemotherapeutic agents, such as doxorubicin and paclitaxel, activate the EZH2/STAT3 signaling pathway, resulting in heightened secretion of exosomes enriched with miR-378a-3p and miR-378d.Upon uptake by chemoresistant tumor cells, these exosomes activate the WNT/β-catenin and Notch signaling pathways by inhibiting the WNT pathway inhibitor DKK3 and the Notch pathway inhibitor NUMB, thereby augmenting the characteristics of the BCSCs and contributing to chemoresistance.