Trimethylated H3K4 and Acetylated H3K14 Expression as Prognostic Markers in Oral Squamous Cell Carcinoma

This study investigated the immunohistochemical expression of histone post-translational modifications (HPTMs) H3K4me2, H3K4me3, and H3K14ac in OSCC and their relationship with metastasis and prognosis. Paraffin-embedded tissue samples of 90 OSCC patients were retrospectively retrieved and immunostained. The sample was divided into primary nonmetastatic (PNM) and primary metastatic (PM) tumors. Nuclear HPTM expression was digitally measured using the integrated optical density index (IOD), and expression levels were divided into low and high based on the median IOD values. Results: All tumor samples were positive. The median H3K14ac IOD was significantly higher in the PM than in the PNM group. High H3K4me2 expression was frequently observed in small and initial tumors, while high H3K4me3 was observed in recurrent OSCC. The ROC curves indicate that H3K14ac might be explored as a screening test for metastasis, showing a sensitivity of 0.81. High H3K4me3-expressing patients had lower survival probabilities and a 3-fold increased risk of death. Conclusions: Our findings suggest that methylation and acetylation of lysine residues 4 and 14 of histone H3 are potential biomarkers of OSCC prognosis and metastasis.