Pathological and Epidemiological Aspects of Meningioma
with Special Emphasis to Sex Hormones

Acta Universitatis Tamperensis No. 1718

By Katariina Korhonen
July 2012
Tampere University Press
ISBN: 9789514487637
132 pages
$82.50 Paper original

There is mounting evidence that sex hormones play an important role in development of meningiomas but the tumorigenesis of meningiomas is still largely unknown. The results of previous studies on hormonal treatments and meningioma risk have been equivocal which makes it difficult to draw any definitive conclusions. Carbonic anhydrases (CA) are enzymes that participate in numerous biological processes in humans, including maintenance of the acid-base balance. CA II and IX have recently been shown to be expressed in several cancers but there is little information on their expression in meningiomas. The purpose of this study was to report the expression of sex hormone receptors and carbonic anhydrases II and IX in meningiomas and evaluate the effect of reproductive factors and exogenous sex hormone exposure on meningioma risk in a population-based case-control study and a cohort study.

We found that most meningiomas expressed progesterone receptors but less than half of them were positive for androgren or estrogen receptors. The expression of all sex hormone receptors was similar in both men and women. Estrogen receptor positive meningiomas had a higher proliferation index than estrogen receptor negative ones. Unlike sex hormone receptors, CA II and IX were rare in meningiomas. CA II expression was more common in atypical and malignant meningiomas than in benign meningiomas. Indicators of endogenous sex hormone exposure were not associated with a meningioma risk, except for an increasing an number of children being directly related to meningioma risk. A non-significant positive association was found between tumors expressing progesterone receptors and use of oral contraceptives. In the cohort study, estradiol-only therapy was associated with an increased meningioma incidence.

Estrogen receptors may have more involvement in pathogenesis of meningiomas than is earlier thought. Expression of carbonic anhydrase II is higher in atypical and malignant meningiomas compared to benign tumors suggesting carbonic anhydrase II may be a target molecule for antitumor therapy when treating of grade II-III meningiomas. Reproductive factors do not seem to have major importance in tumorigenesis of meningiomas. Regarding meningioma risk, combination therapy for postmenopausal symtoms seems to be safer than use of estradiol-only regimen.

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