The cyclin-dependent kinase inhibitor 2A (CDKN2A) and the cyclin-dependent kinase inhibitor 2B (CDKN2B) genes both encode putative regulators of cyclin-dependent kinases on chromosome 9p21 that could lead to uncontrolled cell proliferation and have been associated with poor prognosis in many cancer types included gliomas [23,53,54,55]. The gene discussed is CDKN2A; the disease is cancer.