Cathepsin L in glioma progression: Comparison with cathepsin B

Objective: Lysosomal cysteine cathepsins have been implicated in tumor progression. This study is aimed to reveal differential expression and compare the prognostic significance of cathepsins B and L in glioma patients. Methods: The histological slides of 82 patients with primary astrocytic tumors were reviewed. We evaluated the immunostaining of the cathepsins in tumor and endothelial cells. Results: Cathepsins B and L stained positive in 98 and 88% of cases, respectively. The total score was significantly higher in malignant than in benign tumors, both for cathepsin B (p < 0.001) and for cathepsin L (p < 0.01). The IHC score in endothelial cells in the malignant group was significantly higher only for cathepsin B (p < 0.0001). Survival analysis indicated that in contrast to the prognostic significance of total cathepsin B and endothelial cells associated cathepsin B for shorter patients' survival, the prognostic role of cathepsin L was not confirmed. Conclusion: Cathepsin L is preferentially expressed in tumor cells, increasing with glioma progression, but is not significantly associated with new vasculature of glioblastoma. In contrast to cathepsin B, cathepsin L has no prognostic impact, suggesting different roles of the two cathepsins in glioma progression.