We then constructed an oral cancer vaccine using recombinant B. longum expressing the greatest length of WT1 protein on the cell surface (B. longum 420)13 and demonstrated that B. longum 420 could induce multiple WT1 epitope-specific cellular immunity and significantly inhibit tumor growth in WT-1-expressing mouse prostate cancer and bladder cancer models4,14. Here, WT1 is linked to urinary bladder carcinoma.