| These alterations lead to changes in the expression of several genes ; protein 53 ( p 53 ) , retinoblastoma ( RB ) , interferon ( INF ) alpha / beta , cyclic AMP dependent kinase number 2 ( CDKN 2 ) , mutated in multiple advanced cancers 1 ( MMAC 1 ) , deleted in colon carcinoma ( DCC ) , epidermal growth factor receptor ( EGFR ) , platelet derived growth factor ( PDGF ) , platelet derived growth factor receptor ( PDGFR ) , MDM 2 , GL 1 , CDK 4 and SAS during the genesis and progression of human gliomas . ^^^ |