Expression of bone-morphogenetic protein 2 and tumor necrosis factor α correlates with bone metastases in bladder urothelial carcinoma.

We have investigated the role of bone-morphogenetic protein (BMP) 2 and tumor necrosis factor α (TNF-α) in 33 patients with bladder cancer (BCa) with bone metastasis. Thirty nonmetastatic BCas were included as controls. Immunohistochemical staining with BMP-2 and TNF-α was performed. Expressions of the factors were quantified and studied statistically. As a result, a trend showing higher expression of BMP-2 and TNF-α was associated with advanced disease. Expressions of BMP-2 and TNF-α were significantly higher in BCa with bone metastases (P = .0002 and P = .0172, respectively). The expression of BMP-2 and TNF-α showed a direct correlation in metastatic and muscle-invasive cases (P = .0202 and P = .0004, respectively) but not in nonmetastatic or noninvasive BCa (P = .1834 and P = .9215, respectively). It is postulated that BMP-2 can be responsible for the mechanism involved in triggering bone metastasis in BCa. The correlation with TNF-α indicates that the interaction of the 2 factors may promote local invasion and distant metastasis, especially to bone.