BackgroundAberrant activation of the Wnt/β-catenin signaling pathway is an important factor in the development of nasopharyngeal carcinoma (NPC). Previous studies have demonstrated that the developmental gene sex-determining region Y (SRY)-box 1 (SOX1) inhibits cervical and liver tumorigenesis by interfering with the Wnt/β-catenin signaling pathway. However, the role of SOX1 in NPC remains unclear. This study investigates the function of SOX1 in NPC pathogenesis.ResultsDown-regulation of SOX1 was detected in NPC cell lines and tissues. Besides, quantitative methylation-specific polymerase chain reaction revealed that SOX1 promoter was hypermethylated in NPC cell lines. Ectopic expression of SOX1 in NPC cells suppressed colony formation, proliferation and migration in vitro and impaired tumor growth in nude mice. Restoration of SOX1 expression significantly reduced epithelial-mesenchymal transition, enhanced cell differentiation and induced cellular senescence. Conversely, transient knockdown of SOX1 by siRNA in these cells partially restored cell proliferation and colony formation. Notably, SOX1 was found to physically interact with β-catenin and reduce its expression independent of proteasomal activity, leading to inhibition of Wnt/β-catenin signaling and decreased expression of downstream target genes.ConclusionsSOX1 decreases the expression of β-catenin in a proteasome-independent manner and reverses the malignant phenotype in NPC cells.Electronic supplementary materialThe online version of this article (doi:10.1186/1476-4598-13-257) contains supplementary material, which is available to authorized users.

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Objectives: To evaluate the diagnostic value of narrow-band imaging (NBI) for the detection of nasopharyngeal carcinoma (NPC). Study Design: Prospective study. Setting: Tertiary medical center. Subjects and Methods: Between December 2009 and June 2010, a total of 1,854 patients were examined by means of an electronic nasopharyngolaryngoscope equipped with conventional white light (WL) and an NBI system. The sensitivity, specificity and positive/negative predictive values for detecting NPC were calculated and compared. Results: Of these patients, 62 cases (3.34%) were pathologically confirmed as NPC. The sensitivity, specificity, positive predictive value and negative predictive value for detecting NPC significantly increased from 90.3, 75.4, 11.3 and 99.6% with WL up to 100, 99.2, 81.6 and 100% with NBI, respectively. Conclusion: Our findings suggested that NBI endoscopy might serve as an ideal tool in the detection of NPC.