CDKN1A and glioblastoma: In addition to the ceramide pathway, VD3 was reported to increase the expression of senescence markers, such as cyclin-dependent kinase inhibitor 2A (CDKN2A or also known as INK4A or p16) and cyclin-dependent kinase inhibitor 1A (CDKN1A), due to the upregulation of lysine demethylase 6B (KDM6B) in U87MG and U251 GBM cells [27].