Bone morphogenetic proteins (BMPs) are members of the transforming growth factor-β (TGF-β) family and may play an important role in the regulation of malignant cells in bladder cancer. The aim of the present study was to investigate BMP expression in non-muscle invasive bladder cancer. Tumor tissue samples from 71 patients treated with transurethral resection and 10 samples of normal bladder tissue were stained using immunohistochemistry for BMP-2, -4, -6 and -7. The levels of BMP were correlated with the number and size of tumors in the bladder, the pathohistological findings as well as with tumor recurrence and progression. The results of the present study demonstrated that BMP-2 and -7 are highly expressed in normal bladder tissue, but significantly downregulated in cancer samples. This reduction correlates with a faster rate of tumor recurrence as well as with an increase in the number of recurrent tumors. There was no evident interrelation between BMP-2 and -7 reduction and changes in tumor grade and stage. In conclusion, BMP-2 and -7 are potential prognostic factors for tumor recurrence and further studies on BMP and bladder cancer are needed to confirm these results.
