Abstract. The identification of biomarkers in urine or serum samples from patients with bladder cancer is urgently required for the development of non-invasive methods for the diagnosis of bladder carcinoma and to facilitate follow-up surveillance, to combat the high progression and recurrence rates of this type of cancer. The current study measured the content of matrix metalloproteinase (MMP)-2 and -9, as well as tissue inhibitor of metalloproteinase (TIMP)-1 and -2 in the urine and sera of 41 patients with bladder cancer by ELISA. The association between levels of MMP-2 and -9 and TIMP-1 and -2, and tumor grade and stage were investigated to verify whether these molecules are involved in tumor differentiation. Statistical analysis of the data revealed that urinary TIMP-1 levels were significantly higher in the high grade group compared with those of the low grade samples (P=0.022). The results also revealed a significantly differing distribution of TIMP-1 expression between Ta and T1 stage specimens (P=0.040). The corresponding area under the curves (AUCs) were 0.72, with a sensitivity of 0.70 and specificity of 0.75. In addition, neutrophil gelatinase-associated lipocalin (NGAL) and MMP-9/NGAL complex levels in the sera were measured. All molecules evaluated were detected in the sera of the patients studied. In particular, tumors staged as non-muscle invasive (Ta and T1), demonstrated significantly higher NGAL levels compared with those of muscle invasive (>T1) bladder cancer (32.8 ng/ml vs. 16.2 ng/ml; P=0.029). The discriminatory ability of NGAL expression was confirmed by receiver operating characteristic curve analysis that revealed an AUC of 0.75, a sensitivity of 0.88 and a specificity of 0.67. These data indicated that urinary TIMP-1 and serum NGAL may be useful non-invasive biomarkers to provide clinical information for bladder cancer disease management. Multicenter, prospective studies are required to confirm these preliminary results.
IntroductionBladder cancer (BCa) is one of the most common urologic malignancies worldwide; with a higher frequency amongst males than females (1). The two major environmental risk factors for BCa are high exposure to tobacco smoke, and occupational exposure to aromatic amines, polycyclic aromatic hydrocarbons and chlorinated hydrocarbons (2,3). Furthermore, exposure to ionizing radiation, a variety of lifestyle choices, occupations, dietary factors, drugs, urologic pathologies, family history and genetic polymorphisms may increase the risk of bladder carcinoma (1-3). There are two clinical phenotypes of bladder carcinoma: Non-invasive and invasive BCa. Non-invasive BCa includes the papillary carcinoma phenotype (Ta) and flat carcinoma in situ (cis). Ta bladder carcinoma is superficial and rarely invades the basement membrane or metastasizes, but is associated with a high risk of local recurrence; while invasive bladder carcinoma has a high risk of disease progression, including muscle invasion and metastasis, and mortality. Ta tumorigenesis typically occurs via a mol...