SAHA may increase the expression of acetyl-histones 3 and 4 and thereby down-regulate the mRNA expression of downstream genes, including p21, p27, Cyclin D1, c-myc and Nanog. Overexpression of these acetyl-histones may be positively linked to the tumorigenesis and differentiation of glioma. Here, CCND1 is linked to glioma.