Aberrant expression of CDK5 infers poor outcomes for nasopharyngeal carcinoma patients

Aberrant expression of CDK5 involved in epithelial-to-mesenchymal transition had been reported in various types of cancers, but its functions in nasopharyngeal carcinoma have not been fully clarified yet. The principal purpose of this research was to investigate the clinicopathological significance of CDK5 and its potential effect on NPC carcinogenesis.

Pre-treated formalin-fixed paraffin-embedded biopsy samples of 393 patients between January 2011 and December 2013 were collected for tissue microarrays (TMAs). Immunohistochemistry was performed on sequential TMA sections stained with antibodies against CDK5, EGFR and P53.

The expression of CDK5 in NPC tissues was significantly higher than that in normal nasopharyngeal tissues. Among squamous carcinomas, the expression of CDK5 in undifferentiated tissues was noticeably increased compared with that in differentiated tissues. NPC patients in advanced T category showed a perceptibly higher level of CDK5 than those in early T category. The relative level of CDK5 in NPC sufferers with lymph node metastasis was obviously higher than that of patients without. Compared with patients in early TNM stages, the relative expression level of CDK5 of those in advanced TNM stages was notably up-regulated. Moreover, the CDK5 expression was positively correlated with EGFR and P53 expression. Nevertheless, no significant association was observed between CDK5 and gender, age or histological type.

Overexpression of CDK5 might be considered as a warning signal for NPC. Consequently, CDK5 could serve as a potential target for diagnosis and gene therapy for NPC patients.