Published in Cancer Detection and Prevention 2000; 24(Supplement 1).

Cathepsins B, L and inhibitors stefin A and cystatin C in meningiomas

T Strojnik MD, TT Lah PhD 2, B Židanik MD 3, J Kos PhD 4

Departments of Neurosurgery, 1 and Pathology, 3 Maribor Teaching Hospital, Maribor, Slovenia; National Institute of Biology, Laboratory for Molecular Biology and Biochemistry, Ljubljana, Slovenia, 2 ; Dept Biochemistry and Molecular Biology, Jožef Stefan Institute, Ljubljana, Slovenia, 4 ; Dept Biochemical Research and Drug Design, KRKA, dd, Ljubljana, Slovenia, 4,

AIMS: Meningiomas are benign neoplasms, derived from coverings of the brain. Approximately 10% of benign tumors progress into atypical and malignant tumors, representing a subset of pathologically benign tumors, which are clinically invasive. New prognostic factors, which would differentiate between potentially malignant form(s) of the tumor are needed. METHODS: We evaluated the levels of Cat B and Cat L and the levels of stefin A and cystatin C, in 88 meningiomas by immunohistochemical (IHC) analysis, using mono and polyclonal antibodies. IHC score was determined as the sum of the frequency (0 to 3) and intensity (0 to 3) of immunolabeling of the tumor cells. Two groups with scores 0 to 3 and 4 to 6 were distinguished as weak and strong positive staining, respectively. RESULTS: 21 atypical and 67 benign meningiomas were included into the study. Among the benign group, 9 tumors had some features of malignancy, although a pathologist classified them as benign. IHC score for Cat B in atypical tumors was significantly higher as in the benign tumors (p = 0.004). The same was found for Cat B in atypical vs. clear benign tumors (p = 0.001) and border benign vs. clear benign meningiomas (p = 0.02). There was no statistical difference in IHC staining of Cat B between atypical and border benign meningiomas. For Cat L IHC staining was also significantly different in atypical vs. benign (p = 0.003), in atypical vs. clear benign tumors (p = 0.005) and border benign vs. clear benign meningiomas (p = 0.02). No immunostaining for stefin A and cystatin C was detected. CONCLUSIONS: The findings suggest that Cat B and Cat L are potential diagnostic markers of invasive meningiomas. They may be useful for distinguishing the histomorphologically benign tumor from the histomorphologically benign but invasive meningiomas. We found no immunohistochemical staining of the endogenous cysteine proteinase inhibitors in meningiomas.

KEY WORDS: Cysteine proteinases, meningioma, invasion, extracellular matrix, diagnostic markers.

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Paper presented at the International Symposium on Impact of Biotechnology on Cancer Diagnostic & Prognostic Indicators; Geneva, Switzerland; October 28 - 31, 2000; in the section on prognostic markers.