Article
Expression of Cathepsin B by oligodendrogliomas
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Published: | September 16, 2010 |
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Objective: Human glioma cells were recently reported to secrete Cathepsin B (CB). However, The presence of CB in oligodendrogliomas has not been examined yet. In the present study oligodendrogliomas were examined immunohistochemically for CB-expression. The purpose of this study was to demonstrate the CB-expression and correlation with tumor dedifferentiation oligodendrogliomas.
Methods: 78 oligodendroglioma cases were examined immunohistochemically for CB-expression (male: 34, female: 44). The tumors were classified as grade II (n=46), grade III (n=18), and grade IV (glioblastoma with oligodendroglial growth pattern, n=14). The age varied between 17 and 70 years (mean age 47.5 years female, 43.7 years male).
CB-expression was evaluated qualitatively.
Results: Tumor grading correlated with age (r=0,327, p=0,03) and with CB-expression (r=0,3000, p=0,017).
In grade II oligodendrogliomas, CB was detected in significantly fewer cases (n=46, CB-positive: 17, 7 cases censored) than in grade III oligodendrogliomas (n=18, CB-positive: 9, 4 cases censored) and grade IV glioblastomas with oligodendroglial growth pattern (n=14, CB-positive: 10, 3 cases censored), p=0,017. Grading also correlated significantly with the age of the patients (r=0,327, p=0,03). Kaplan Meyer survival statistics of 52 cases, in whom catamnestic data was available, revealed a significantly shorter survival of patients with tumors expressing CB (log Rank statistics, p=0.02). The mean survival time of patients with CB-positive oligodendrogliomas was 66 months (n=31, 9 cases censored), whereas patients with CB-negative tumors had a mean survival time of 109 months (n=21, 12 cases censored). However, in multivariate Cox regression computed for grading, gender, age and CB-expression only tumor grading was statistically significant (p=0.002).
Conclusions: Oligodendrogliomas of all grades express CB and it correlates with the tumor grading. CB may participates in the proteolysis and decomposition of ECM and BM components such as laminin, fibronectin and type IV collagen.
It can be speculated that infiltration of leptomeninx by oligodendroglial tumors among other factors depends on the expression of cathepsin B. CB-expression in high-graded oligodendrogliomas has a reciprocal relationship with the mean survival time and can be considered as a prognostic indicator.