Expression of Acetylated and Dimethylated Histone H3 in Colorectal Cancer

Abstract

Aim: The expression of acetylated and dimethylated histone H3 in colorectal cancer was examined by immunohistochemistry and chromatin immunoprecipitation (ChIP)/Western blot (WB) assay. The correlation between the expression of histone H3 and clinicopathological findings was analyzed. Methods: Formalin-fixed and paraffin-embedded sections obtained from 80 operated cases of colorectal cancer were immunostained with anti-acetylated histone H3 (H3Ac) antibody and anti-dimethylated histone H3 lysine 4 (H3K4) antibody. Positive immunoreactivity was evaluated using the Allred scoring system. Furthermore, the expression was confirmed by ChIP/WB assay using formalin-fixed and paraffin-embedded sections. Results: There was good correlation between immunostaining and expression on ChIP/WB assay (p = 0.0005). There was a significant difference between the Allred score of H3K4 and the depth of tumor invasion (p = 0.0003) and the pathological stages (p = 0.0065). In overall survival classified by Allred scores of H3Ac (p = 0.0072) and H3K4 (p = 0.0187), the highest scores represented significantly worse prognoses than the other scores. Specifically, in stages II and III, the highest scores represented significantly worse prognoses than the other scores (p < 0.0001 and p = 0.0173, respectively). Conclusion: The expression of H3Ac and H3K4 may estimate patient prognosis.