Reduced expression of Dicer11 is associated with poor prognosis in patients with nasopharyngeal carcinoma

Dicer11 plays an important role in generation of microRNA and is dysregulated in a variety of human cancers. The purpose of this study was to evaluate Dicer11 expression and its prognostic value in nasopharyngeal carcinoma (NPC). The protein expression of Dicer1 was examined by immunohistochemistry in 276 NPC specimens, and the mRNA levels of Dicer1 were analyzed by qRT-PCR in 56 NPC and 11 nasopharyngitis tissues. Cox regression analysis was used to identify independent prognostic factors, and a prognostic score model was constructed for survival prediction. Expression of Dicer1 was downregulated in NPC tissues at both the mRNA and the protein levels, and there was a notable positive correlation between the expression levels of Dicer1 mRNA and protein. Low Dicer1 expression was positively correlated with distant metastasis (P < 0.01) and death (P = 0.01). In addition, low expression of Dicer1 was significantly associated with poorer overall survival (HR, 2.32; 95 % CI 1.30-4.14; P < 0.01) and poorer distant metastasis-free survival (HR, 2.56; 95 % CI 1.39-4.74; P < 0.01). Furthermore, multivariate analysis showed that low expression of Dicer1 and tumor-node-metastasis (TNM) stage was independent prognostic indicators for NPC patients. A prognostic score model combining the Dicer1 expression and TNM stage had a better prognostic value than the TNM stage alone model or Dicer1 expression alone model (P < 0.05). Dicer1 was downregulated in NPC tissues at both the mRNA and the protein levels, and low expression of Dicer1 could be served as novel prognostic biomarker for NPC patients.