POU5F1 and urinary bladder cancer: Furthermore, knockdown of Oct4 expression in bladder cancer cells does not affect their sensitivity to mitomycin C. Taken together, these results suggest that Oct4 either directly or indirectly contributes to the cross-resistance of bladder cancer cells to the chemotherapeutic drugs used for patients with bladder cancer, including cisplatin, 5-FU, doxorubicin, paclitaxel, gemcitabine, and methotrexate.