HDAC8 and neoplasm: Corresponding to these in vitro data, quantitative immunohistochemical analysis of the dissected tumor material from the HDAC8-inhibitor-treated mice revealed an increase in neurofilament-positive tumors (7/12=58.3%) compared with control groups (1/12=8.3%), and a significantly lower amount of cells positive for phosphorylated histone H3, a marker for mitosis (Figure 4).