High nuclear protein kinase C θ expression may correlate with disease recurrence and poor survival in oral squamous cell carcinoma

Summary Protein kinase Cs play important roles in many biological processes and tumorigenesis. This study examined the expression of protein kinase C θ and assessed its significance in patients with oral squamous cell carcinoma. Immunohistochemical staining was carried out to investigate the expression of protein kinase C θ in 59 cases of oral squamous cell carcinoma. The results were correlated with clinical characteristics and outcome of patients. Diffuse cytoplasmic protein kinase C θ was identified in 53 (89.8%) of the 59 oral squamous cell carcinoma cases, and the expression was not statistically associated with any clinicopathologic parameter. Twenty (40.7%) of the 59 oral squamous cell carcinoma cases exhibited nuclear expression of protein kinase C θ with different grade of intensity. χ2 analysis indicated that high nuclear protein kinase C θ expression correlated significantly with shorter 24-month survival ( P = .043) and disease recurrence ( P = .019). The Kaplan-Meier method also showed that high nuclear expression of protein kinase C θ was significantly associated with poor overall survival ( P = .034) and shorter time to recurrence ( P = .003). Univariate analysis revealed that high nuclear protein kinase C θ expression ( P = .046; hazard ratio, 2.2), tumor size less than 2 cm ( P = .049; hazard ratio, 4.7), lymph node metastasis ( P = .003; hazard ratio, 3.0), and higher stage ( P = .002; hazard ratio, 8.7) were each associated with shorter overall survival. We identified the aberrant nuclear expression of protein kinase C θ in oral squamous cell carcinoma. High nuclear protein kinase C θ expression may correlate with disease recurrence and poor survival in patients with oral squamous cell carcinoma.