Lack of Correlation Between Immunohistochemical Expression of SPARC and Invasion in Different Grades of Meningiomas.

BACKGROUND: Grade I meningiomas are generally benign and non-invasive whereas Grade II (atypical) and Grade III (malignant) meningiomas tend to be invasive with a high risk of recurrence. SPARC, secreted protein, acidic and rich in cysteine, is a multifunctional glycoprotein which has been proposed to be a potential diagnostic marker of invasive meningiomas. There has been increased reporting of atypical meningiomas since the current World Health Organization (WHO) included brain invasion as a grading criterion for classification of these particular meningiomas. MATERIALS AND METHODS: The aim of this study was to re-evaluate any correlation between immunohistochemical expression of SPARC in 34 meningiomas of various grades using the current classification (2016). We had previously classified these cases using the 2002 WHO criteria. RESULTS: There is no correlation between expression of SPARC and invasion in different grades of meningioma. CONCLUSION: SPARC does not appear to be a good predictor of invasion in meningiomas.

Comparative gene expression profiling of ADAMs, MMPs, TIMPs, EMMPRIN, EGF-R and VEGFA in low grade meningioma.

MMPs (matrix metalloproteinases), ADAMs (a disintegrin and metalloproteinase) and TIMPs (tissue inhibitors of metalloproteinases) are implicated in invasion and angiogenesis: both are tissue remodeling processes involving regulated proteolysis of the extracellular matrix, growth factors and their receptors. The expression of these three groups and their correlations with clinical behaviour has been reported in gliomas but a similar comprehensive study in meningiomas is lacking. In this study, we aimed to evaluate the patterns of expression of 23 MMPs, 4 TIMPs, 8 ADAMs, selective growth factors and their receptors in 17 benign meningiomas using a quantitative real-time polymerase chain reaction (qPCR). Results indicated very high gene expression of 13 proteases, inhibitors and growth factors studied: MMP2 and MMP14, TIMP-1, -2 and -3, ADAM9, 10, 12, 15 and 17, EGF-R, EMMPRIN and VEGF-A, in almost every meningioma. Expression pattern analysis showed several positive correlations between MMPs, ADAMs, TIMPs and growth factors. Furthermore, our findings suggest that expression of MMP14, ADAM9, 10, 12, 15 and 17, TIMP-2, EGF-R and EMMPRIN reflects histological subtype of meningioma such that fibroblastic subtype had the highest mRNA expression, transitional subtype was intermediate and meningothelial type had the lowest expression. In conclusion, this is the first comprehensive study characterizing gene expression of 8 ADAMs in meningiomas. These neoplasms, although by histological definition benign, have invasive potential. Taken together, the selected elevated gene expression pattern may serve to identify targets for therapeutic intervention or indicators of biological progression and recurrence.