['This study retrospectively evaluated the prognostic significance of downregulated protocadherin-10 (PCDH10) gene expression in bladder cancer.', 'To evaluate the prognostic significance of downregulated PCDH10 protein levels, immunohistochemistry was used to assess the level of PCDH10 protein in surgically-resected formalin-fixed, paraffin wax-embedded transitional cell carcinoma specimens. Relationships between PCDH10 protein levels, clinicopathological characteristics and overall survival were also evaluated.', 'A total of 105 bladder transitional cell carcinoma specimens and 33 normal bladder epithelial samples were investigated using immunohistochemical staining. PCDH10 protein levels were downregulated in 63.8% (67/105) of bladder cancer specimens compared with control samples. Downregulated levels of PCDH10 were significantly associated with advanced stage, higher grade, larger tumour size, nonpapillary shape, tumour recurrence and decreased overall survival rates. Multivariate analysis indicated that downregulated PCDH10 levels were independently associated with decreased overall survival and had a relative risk of death of 4.571.'] Does downregulation of protocadherin-10 expression correlate with malignant behaviour and poor prognosis in human bladder cancer?