Expression of cathepsin D in bladder carcinoma:: Correlation with pathological features and serum cystatin C levels

Aims and background: The aim of this study is to evaluate the expression of cathepsin D in primary bladder cancer and to determine its relationship with conventional pathological features and serum cystatin C levels. Methods: The immunohistochemical cathepsin D expression and staining patterns of epithelial and stromal cells were investigated in 21 patients with primary bladder carcinoma. Serum cystatin C levels were determined by immunoturbidimetry and compared with matched controls. Results: There were 7 papillary neoplasms of low malignant potential, 7 low-grade and 7 high-grade carcinomas. Six tumors were invasive. Statistical analysis showed a significant inverse relationship between cathepsin D expression of the tumor cells and tumor grade and stage (P = 0.018 and P = 0.046, respectively). Serum cystatin C levels of the controls and patients varied between 0.39 mg/L and 1.99 mg/L (P > 0.05). There was no significant relation between cathepsin D expression in tumor tissue and serum cystatin C levels. Conclusions: Loss of cathepsin D expression in bladder carcinomas may be associated with high-grade and invasive tumors. Thus, increased cathepsin D expression by tumor cells may be related to local tumor invasion at an early stage, but it seems that extracellular cystatin C is not affected by cathepsin D expression of tumor or stromal cells, and cystatin C concentrations are not directly correlated with the progression of primary bladder carcinomas.