POSTN and urinary bladder cancer: In their study, immunohistochemical analysis using tissue microarray revealed that periostin reactivity in muscle-invasive bladder cancer cells (i.e., epithelial expression) was correlated with worse patient prognosis, and there was no significant correlation between epithelial periostin expression and the recurrence of non-muscle-invasive bladder cancers [20], consistent with another study [32].