They found that meningiomas were 11 times more frequent in patients with MEN1 and Zollinger–Ellison (ZES) syndrome than with ZES alone and demonstrated that allelic loss at MEN1 but not at NF2 gene locus and frequent alterations in sporadic meningiomas play a role in the pathogenesis of MEN1-associated meningioma (71). This evidence concerns the gene MEN1 and Zollinger-Ellison syndrome.