CDKN2D and malignant glioma: Using recombinant adenoviral vectors that express CDKIs (p16INK4A, p18INK4C, p19INK4D, p21WAF1/CIP1 and p27KIP1), we compared the antitumour effect of CDKIs on malignant glioma cell lines (A172, GB-1, T98G, U87-MG, U251-MG and U373-MG).