Expression of programmed cell death protein 4 (PDCD4) and miR-21 in urothelial carcinoma

BackgroundWe investigated the role of the programmed cell death 4 (PDCD4) tumor suppressor gene in specimens of transitional cell carcinoma and of healthy individuals.MethodsPDCD4 immunohistochemical expression was investigated in 294 cases in histologically proven transitional cell carcinoma in different tumorous stages (28 controls, 122 non-muscle invasive urothelial carcinoma, stages Tis-T1, 119 invasive transitional cell carcinoma stages T2–T4 and 25 metastases). MiR-21 expression, an important PDCD4 regulator, was assessed with real-time PCR analysis and showed inverse correlation to tissue PDCD4 expression.ResultsNuclear and cytoplasmatic PDCD4 immunostaining decreased significantly with histopathological progression of the tumor (p < 0001). Controls showed strong nuclear and cytoplasmatic immunohistochemical staining. MiR-21 up regulation in tissue corresponded to PDCD4 suppression.ConclusionsThese data support a decisive role for PDCD4 down regulation in transitional cell carcinoma and confirm miR-21 as a negative regulator for PDCD4. Additionally, PDCD4 immunohistochemical staining turns out to be a possible diagnostic marker for transitional cell carcinoma.

► The tumor suppressor gene PDCD4 is down-regulated in many tumorous entities.
► We investigate the impact of PDCD4 and its regulating factor miR-21 in urothelial carcinoma.
► We confirm PDCD4 as a tumor suppressor gene and it could be a diagnostic marker for this tumor.