ARID1B and breast cancer: Karyopherin subunit beta 1 (KPNB1), also a member of the Karyopherin family of importins, plays an instrumental role in the nuclear import of various proteins that contribute to breast cancer progression, metastasis, and drug resistance.[58] Recent studies also showed that KPNB1 is highly expressed in breast cancer and is associated with tumor progression and poor prognosis.[57, 58, 59] To study the role of KPNB1 in regulating ARID1B, we examined the effect of KPNB1 blockade using the inhibitor importazole (IPZ).