CDKN2D and malignant glioma: To address these issues, in the present study, we compared the antitumour effect of CDKIs on malignant glioma cell lines and cultured astrocytes by using recombinant adenoviral vectors that express CDKIs (p16INK4A, p18INK4C, p19INK4D, p21WAF1/CIP1 and p27KIP1).