The global histone modification patterns of osteosarcoma

Background: Epigenetic alteration may affect a patient's prognosis by altering the development and progression of the tumor. Some recent reports have identified a correlation between histone modification and patient outcome. However, no studies have been conducted on global histone modification in osteosarcomas. Methods: We investigated histone modification in 54 cases of osteosarcoma by performing immunohistochemical staining. The immunohistochemical expression of four histone modification markers, acetylated H4 lysine 12 (H4K12Ac), acetylated H3 lysine 18, trimethylated H3 lysine 27, and dimethylated H3 lysine 4 were evaluated. Results: High H4K12Ac expression was correlated with patient age (p=0.011). However, the other histone modification markers showed no correlation with any of the clinicopathological data such as survival, tumor grade, tumor site, metastasis, age, or gender. Conclusions: Our study showed that all four histone modification markers are expressed in osteosarcoma (median expression rate, 40 to 60%). However, we did not find a correlation with the clinicopathological factors except for age. Further study to evaluate the reason for the association between H4K12Ac and patient age is needed.