FOXP3 and urinary bladder cancer: In one study, immunohistochemical analysis of bladder biopsies showed increased numbers of cells expressing: (1) signal transducer and activator of transcription 4 (STAT4), which plays a key role in the differentiation of Th1 cells [159], and (2) Foxp3, a marker for Tregs, in patients with Sh-associated bladder cancer, compared to patients with bladder cancer without Sh infection.