CDKN2A and meningioma: In our functional studies, we show that our primary meningioma cell lines that are Rb-deficient, also have higher CDKN2A expression compared to the p16-deficient, Rb-intact CH157 and IOMM-LEE meningioma cell lines, and that these primary Rb-deficient cell lines are resistant to treatment with both abemaciclib and palbociclib [21].