Introduction: Matrix metalloproteinase-9 (MMP-9) has a role in the destruction of lamina propria (LP) of the bladder wall and SMAD-2 promotes cell-to-cell adhesion. This study aimed to investigate the association between LP invasion and serum protein and mRNA expression levels of MMP-9 and SMAD-2 in bladder cancer (BC) patients. Methods: Serum samples were taken from 57 patients with suspicious BC before TUR-BT (Group 1) and 20 patients with benign diseases as control (Group 2). The mRNA expression and serum protein levels of MMP-9 and SMAD-2 were analyzed using Real-Time PCR and ELISA methods, respectively. The comparison of protein and mRNA expression levels of MMP-9 and SMAD-2 were done statistically between Group 1 and 2, as well as for different T stages of BC. Results: The protein levels of MMP-9 (2448 vs 637.5 pg/mL, P =.0001) and SMAD-2 (6.85 vs 1.61 P =.0001) were significantly higher in Group 1 compared to Group 2. The mRNA expression levels of MMP-9 (P =.89) and SMAD-2 (P =.99) did not significantly differ between the groups. The protein levels of MMP-9 in T1 patients were significantly higher from both of pTa patients (P =.018) and pT2 (P =.02). The protein levels of SMAD-2 were not statistically different between T stages. Similarly, the mRNA expression levels of MMP-9 and SMAD-2 were not different between T stages. Conclusions: The protein levels of MMP-9 and SMAD-2 were increased in BC patients while mRNA expressions were not different. Furthermore, the increased protein level of MMP-9 in T1 patients was more pronounced which may be related to LP invasion of the tumor.
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