Expression and prognostic significance of the MMP family molecules in bladder cancer

Background: Bladder cancer (BC) is the 10th most common cancer worldwide with significantly varied prognosis in different pathological subtypes. MMPs, a group of enzymes, could involve in the invasion and metastasis of numerous malignancies. The function of MMPs in BC is partly reported in several studies but with a great conflicts; hence, a systematic analysis of expression levels and prognostic values of these MMP genes are still to be determined. Methods: Firstly, differentially expressed genes (DEGs) of MMPs were identified in ONCOMINE, GEPIA and UALCAN databases; and these DEGs were also detected by real-time RT-qPCR. More importantly, we investigated the clinical significance of these DEGs in BC patients via Kaplan-Meier (KM) Plotter, UALCAN and cBioPortal databases. Results: The study found that mRNA expression of MMP1/11 in BC samples was significantly higher than that in normal bladder tissues, and MMP2/3 were lower in the former than in the latter. The expression level of MMP1/2/7/9/11/13/23B were significantly related to the tumour stages. Furthermore, the prognostic analysis suggested that the high transcription levels of MMP7 and low transcription levels of MMP23A were correlated with favorable relapse-free survival and overall survival in the patients with BC, respectively. Notably, high MMP11/13 expression levels indicated poor overall survival (OS) and relapse-free survival (RFS) in patients with BC. Conclusion: This study revealed that MMP1/2/3/7/9/11/13/23A/23B are possible prognostic biomarkers and clinical therapeutic targets for patients with BC.