Decreased P27 protein expression is correlated with the progression and poor prognosis of nasopharyngeal carcinoma

BACKGROUND To determine the correlation of cyclin-dependent kinase inhibitor 1B (p27) expression with clinicopathologic features in nasopharyngeal carcinoma (NPC), including patient prognosis. METHODS Real-time PCR and immunohistochemistry were used to examine the mRNA and protein expressions of p27 in NPC and nasopharyngeal tissues. The relationship of p27 expression levels with clinical features and prognosis of NPC patients was analyzed. RESULTS The expression level of p27 mRNA was markedly lower in NPC tissues than that in the nasopharyngeal tissues (P = 0.0006). Specific p27 protein staining by immunohistochemistry was found in the nuclei and cytoplasm of nasopharyngeal and malignant epithelial cells but decreased expression was observed in NPC samples compared to normal epithelium samples (P = 0.002). In addition, low levels of p27 protein were inversely correlated with the status of T classification (p = 0.002) and clinical stage (p = 0.019) of NPC patients. Patients with lower p27 expression had a significantly shorter overall survival time than did patients with high p27 expression. Multivariate analysis suggested that the level of p27 expression was not an independent prognostic indicator (p = 0.682) for NPC survival. CONCLUSION Low level of p27 expression is a potential unfavorable prognostic factor for patients with NPC. VIRTUAL SLIDES The virtual slide (s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1915282782109343.