Overexpression of PBX1 promoted cell proliferation and enhanced the resistance of PCa cells to doxorubicin and cisplatin. USP9x was a PBX1‐specific deubiquitinase and, which promoted the degradation of PBX1 by increasing its Lys‐48‐linked polyubiquitination. Here, USP9X is linked to posterior cortical atrophy.