CDKN2A and central nervous system cancer: Although 9p losses can be found in many gliomas, they more commonly occur in higher grade tumors (grades 3 and 4), which make the CDKN2A gene or p16 protein (CDKN2A product) potential players involved in the malignant progression and anaplastic transformation of low-grade gliomas into higher grades (He et al., 1995; Ueki et al., 1996; Watanabe et al., 2001).