Staining of interleukin-10 predicts clinical outcome in patients with nasopharyngeal carcinoma

BACKGROUND: Interleukin-10 (IL-10) has been implicated as an important modulator of lymphoid cells, and its sequence is homologous to an open reading frame in the Epstein-Barr virus (EBV) genome. Nasopharyngeal carcinoma (NPC) is a representative tumor related to EBV infection. METHODS: The authors investigated the expression of IL-10 in 21 primary NPCs by using an immunohistochemical approach to examine its prognostic significance. RESULTS: IL-10 staining was positive in 12 of 21 primary NPCs (57%). There was no association between IL-10 expression and gender, tumor size, the occurrence of lymph node metastases, clinical stage, or recurrence. However, there was a significant difference in overall survival between the negative expression and positive expression of IL-10 (P = 0.0348). Although 87.5% of the IL-10 negative group survived for 5 years, only 15.6% of IL-10 positive patients survived for that length of time by the Kaplan-Meier method. IL-10 expression was significant as an independent prognostic indicator of overall survival by multivariate analysis using the Cox proportional hazards model (odds ratio, 26.64; P = 0.0019). CONCLUSIONS: The results imply that expression of IL-10 is a prognostic factor in patients with NPC and may prove valuable in selecting patients with NPC who are candidates for aggressive therapy.