Pediatric nasopharyngeal carcinoma: Better prognosis and increased c-kit expression as compared to adults

Introduction. Nasopharyngeal carcinoma (NPC) in children is distinguishable from the adult form by its close association with Epstein-Barr virus (EBV) infection, a higher rate of undifferentiated histology, and a greater incidence of advanced locoregional disease. Patients and Methods. Sixteen NPC patients, <= 20 years of age were identified from our 1976-2001 tumor registry records. Clinical stage, treatment, recurrence, and survival were evaluated. Sections were stained by immunohistochemistry for p53, Bcl-2, Ki67, and c-Kit and by in situ hybridization for EBER. Obtained data were compared to 32 adult patients. All patients had undifferentiated or non-keratinizing NPC. Results. EBER was positive in 100% of children, compared to 90% of adults. Comparing children to adults, median Ki67 index was 49% and 30%, p53 positive tumors were 69% and 94%, positive Bcl-2 was 63% and 72%, and positive c-Kit was 88% and 28%, respectively. Conclusion. No parameter had significant predictive values for survival, although c-Kit expression had a trend for better prognosis in the pediatric group. By univariate analysis of all 48 cases, positive c-Kit was associated with better survival (P=0.029), largely due to the better survival of the pediatric group. By multivariate analysis, increased stage (P=0.006) and older age (P=0.044) correlated with worse prognosis.