Loss of the putative tumor suppressor protein spinophilin is associated with poor prognosis in head and neck cancer

The putative tumor suppressor protein spinophilin has been recently involved in the pathogenesis of lung, liver, and other types of cancer. Previous studies also indicate that a loss of spinophilin in combination with functional impairment of p53 drives tumor progression. To date, no data exist about the role of spinophilin in head and neck squamous cell carcinoma (HNSCC). In the present study, we evaluated spinophilin and p53 expression by immunohistochemistry in 85 patients with nonmetastatic HNSCC. Kaplan-Meier curves and multivariate Cox proportional models were used to define the prognostic relevance of spinophilin for patients with HNSCC. Overall, immunoreactivity for spinophilin was reduced in 40 tumors (47%). Nine cases (10.5%) showed complete loss of spinophilin. Kaplan-Meier curve analysis demonstrated that reduced spinophilin expression is associated with poor overall survival (P =.022). Concomitant analysis of spinophilin and p53 further showed that patients with reduced spinophilin expression and nuclear p53 staining have a significantly decreased overall survival (hazard ratio, 1.96; 95% confidence interval, 1.06-3.61; P =.030). In conclusion, the combination of reduced spinophilin expression and nuclear p53 staining indicates a poor prognosis in HNSCC patients. Based on our results, spinophilin might play a previously unrecognized role in the pathogenesis of HNSCC.