The biology of meningiomas.

Meningiomas, long neglected as a subject for biological studies, are now being examined more widely as their potential for clinical recurrence and malignancy has been recognized. Most laboratory studies have focused on descriptive analyses of the content of various molecules in ex vivo specimens removed at surgery. Perturbative experiments using cultured cells are possible, but they are complicated by senescence of the cells. The respective importance of the sex steroids (estrogen, progesterone, and androgens), classical growth factors, angiogenic factors, and proteolytic enzymes in the biological behavior of meningiomas is now apparent and is coming under more detailed scrutiny. As general theories of neoplasia crystallize in other systems, the ability of meningiomas to proliferate, invade, and provoke neovascularization will be better understood.