CDKN2A and central nervous system cancer: Thirteen well known genetic risk variants in TERT, EGFR, CCDC26, CDKN2A, CDKN2B,PHLDB1, TP53, and RTEL1 were selected for investigation of possible correlations with the glioma somatic markers: EGFR amplification, 1p/19q codeletion and protein expression of p53, Ki-67, and mutated IDH1.