NUMB and cancer: Conversely, MSI2 is a crucial regulator of cancer stem cell programs by acting on the stability and translation of target mRNAs that encode key proteins of oncogenic signaling pathways (e.g., TGFβR1/SMAD3, NUMB/Notch, PTEN/mTOR, MET, and MYC) [25,26,27,28,29].