Aberrant SATB1 expression is associated with Epstein-Barr virus infection,metastasis and survival in human nasopharyngeal cells and endemic nasopharyngeal carcinoma

Special AT-rich sequence-binding protein 1 (SATB1) has been identified as a key factor in the progression of some cancers, functioning as a global genome organizer and chromatin regulator. We examined the levels of SATB1 mRNA expression in NPC cell lines 5-8F (high metastasis) and 6-10B (low metastasis) and immortalized human nasopharyngeal epithelial cells NP69-SV40T by quantitative real-time PCR. We also examined the protein expression levels of SATB1 in 72 cases of nasopharyngeal carcinoma (NPC) tissues and 30 cases of normal nasopharyngeal (NNP) tissues by immunohistochemistry, and then assessed the correlations between SATB1 expression and clinicopathological factors. The expression level of SATB1 mRNA in 5-8F was much higher than those in 6-10B and NP69-SV40T (P < 0.05). The expression level of SATB1 mRNA in 6-10B was higher than in NP69-SV40T, but the difference was not statistically significant (P > 0.05). The positive expression rates of SATB1 protein in NPC (38/72, 52.8%) were significantly higher than in NNP (4/30, 13.3%) (P < 0.05). SATB1 protein levels in NPC were not associated with gender, age, and T stage (P > 0.05), but positively correlated with the titers of EBVCA-IgA, metastasis (N and M stage), recurrence, and survival (P < 0.05). Multivariate analysis showed that the overexpression of SATB1 protein is an independent prognostic factor for NPC. The expression levels of SATB1 were obviously upregulated in primary NPC tissues and human NPC cell lines. Therefore, SATB1 may be a valuable predictor in assessing the metastasis, recurrence, and prognosis of NPC.