Chapter 1 - Epidemiology, Pathogenesis and Risk Factors of Brain Tumours
Across countries and populations, the incidence of brain tumours is related to gender, with opposite patterns for meningiomas and gliomas. The male/female ratio for meningioma is approximately 0.4 (1 man for 2.5 women).
This difference suggests that sex hormones and/or genetic differences between males and females may play a role in the occurrence of these tumours.
Hormonal receptors were identified in meningioma tissues: ≈80% of meningiomas have progesterone receptors, 40% oestrogen receptors and 40% androgen receptors.
Menopausal hormone therapy is associated with an increased meningioma risk. A recent meta-analysis suggests an increased risk in users of oestrogen-only hormone therapy.
Oral contraception and breast-feeding do not appear to increase the risk of meningioma.
To date, among exogenous suspected factors (electromagnetic fields, nutrition, pesticides, etc.), the only established causal link with risk of meningioma is high doses of ionising radiation.
Increased risk of meningioma is observed in rare hereditary syndromes, mainly neurofibromatosis Type 1 and 2 (NF1 and NF2), and possibly in Turner’s syndrome and Werner’s syndrome.
Germline and somatic mutations in meningiomas: a significant increase in risk of meningiomas is associated with neurofibromatosis Type 2 disease through mutation of the NF2 gene, and approximately 5% of individuals with schwannomatosis develop meningiomas, through mutation of the SWI/SNF chromatin remodeling complex subunit, SMARCB1.
Revision Questions
- Which primary CNS tumour has the lowest sex ratio (male/female)?
- It is recommended to prescribe hormone therapy to menopausal women with meningioma. True or false?
- What are the two main histological types of primary CNS tumour associated with NF2 gene mutation?
