Prognostic significance of nuclear pSTAT3 in oral cancer

Background Aberrant nuclear accumulation of proteins influences tumor development and may predict biologic aggressiveness and disease prognosis. This study determined the prognostic significance of pSTAT3 (phosphorylayed signal transducer and activator of transcription 3) in oral squamous cell carcinomas (OSCCs). Methods and Results Using immunohistochemistry, a significant increase in nuclear accumulation of pSTAT3 was observed in 49 of 90 leukoplakias (54.4%) and 63/94 OSCCs (67%) (p_trend <.001). Increased pSTAT3 was associated with tumor stage (p =.01), nodal metastasis (p =.0018), and tobacco consumption (p =.004). Kaplan-Meier analysis demonstrated that OSCC with increased nuclear pSTAT3 showed significantly reduced disease-free survival (13 months), compared with the patients with no nuclear pSTAT3 expression (64 months, p =.019). Cox regression analysis revealed nuclear pSTAT3 as the most significant predictor of poor prognosis (p =.024, hazard ratio [HR] = 2.7). Conclusions Increased nuclear accumulation of pSTAT3 occurs in early premalignant stages and is a marker for poor prognosis of OSCC.