Expression of bone morphogenetic protein-2 and -7 in urinary bladder cancer predicts time to tumor recurrence

INTRODUCTION Urinary bladder cancer patients who have undergone transurethral resection of bladder tumor (TURBT) are at risk of recurrence. This study aims to correlate the level of bone morphogenetic protein (BMP) expression with urothelial carcinoma invasiveness, TNM stage and time to recurrence after TURBT. MATERIAL AND METHODS In 33 specimens of healthy transitional epithelium and 42 of urothelial carcinoma, BMP2, BMP4 and BMP7 expression was determined by real-time polymerase chain reaction. Patients who underwent TURBT were followed up for 1 year. RESULTS BMP2 and BMP7 were downregulated in infiltrating urothelial carcinoma, the relative expression being 0.76 (p = 0.04) and 0.28 (p = 0.025) respectively, while BMP4 was downregulated in non-invasive tumors. High expression of BMP2 and BMP7 correlated with prolonged time to recurrence (log-rank: p = 0.01 and p = 0.03 respectively). CONCLUSIONS Low expression of BMP2 and BMP7 is associated with shorter time to recurrence. The BMP expression levels are not indicative of tumor stage.