By using immunohistochemistry and Western blotting (Fig. 3E ∼ 3G), we found increased S100A9 in the bladder mucosa and muscles of EAC mice (Fig. 3E ∼ 3 F), particularly in IC/BPS patients (Fig. 3G, p < 0.001). Here, S100A9 is linked to Bartsocas-Papas syndrome 1.