Furthermore, the homozygous loss of CDKN2A/B, located in chromosome 9p21, which represents another defining criterion for malignant meningiomas, encodes for several tumor suppressor proteins, such as p16, which prevent the transition of the G1 phase to the S phase in mitosis, leading to the dysregulation of the cell cycle [1,92]. This evidence concerns the gene CDKN2A and meningioma.