Abstract: Objective To evaluate the correlation of p27 protein expression in the cytoplasm with the clinicopathologic features
of nasopharyngeal carcinoma (NPC). Methods Immunohistochemistry was employed to examine P27 protein expression in the
cytoplasm of NPC samples and nasopharyngeal (NP) tissue samples. The differential expression of P27 protein between NPCs
and NPs and the correlation of cytoplasmic P27 protein expression with the clinicopathologic parameters of NPC patients was
analyzed. Results Immunohistochemistry indicated significantly down-regulated t p27 protein expression in NPC tissues
compared to that in NP tissues (P=0.047). The reduction of P27 expression was inversely correlated with T classification of NPC
(P=0.033). Although cytoplasmic p27 protein expression was not significantly correlated with lymph node metastasis (P=0.157)
or clinical stages of NPC (P=0.090), an obvious trend of inverse correlations between them was noted. Conclusion
Down-regulated cytoplasmic p27 protein expression may promote the carcinogenesis of NPC and can be an unfavorable
prognostic factor for survival of NPC patients.