Objectives: To detect the p16(INK4A) protein expression in salivary adenoid cystic carcinoma(ACC) and evaluate its association with promoter methylation and clinical and pathological characteristics. Methods: Sixty patients with ACC were collected for this study. Expression of p16(INK4A) was detected by immunohistochemistry on paraffin-embedded sections. The results were compared with promoter methylation status which were showed in our previous study. The association between the p16(INK4A) expression with clinical and pathological characteristics were also analyzed. Results: Of the 60 tumors, p16(INK4A) expression was positive in 24 tumors(40%). Loss of p16(INK4A) expression was significantly correlated with the promoter methylation (
P<0.05). p16(INK4A) expression was higher in high-grade tumors than in low-grade tumors(
P<0.05).There were no difference between p16(INK4A) expression and clinical stage of ACC, neither between the tumors with and without metastasis. Conclusions: Loss of expression of p16(INK4A) is common in ACC and abberent promoter methylation may be crucial for silencing of p16(INK4A). Alterations of p16(INK4A) gene may play a role in tumor differentiation.