Overexpression of cyclin E messenger ribonucleic acid in nasopharyngeal carcinoma correlates with poor prognosis

AIMS: S-phase kinase-associated protein 2 is required for the degradation of p27 protein, which is a negative regulator of cyclin E/cyclin-dependent kinase 2 complex. The present study examined the expression of cyclin E, S-phase kinase-associated protein 2 and p27 protein in nasopharyngeal carcinoma. METHODS: Tissue from 35 cases of nasopharyngeal carcinoma and 10 normal nasopharyngeal tissue samples underwent reverse polymerase chain reaction to detect messenger ribonucleic acid. Immunohistochemical analysis was performed on 29 nasopharyngeal tissue samples in order to detect protein expression. RESULTS: Messenger ribonucleic acid expression in the nasopharyngeal carcinoma tissue samples analysed indicated a 1.75-fold change in the amount of S-phase kinase-associated protein 2, a 0.34-fold change in the amount of cyclin E and a 0.31-fold change in the amount of p27 protein, compared with positive controls. High levels of cyclin E significantly correlated with late-stage nasopharyngeal carcinoma (p = 0.009) and a poor overall survival (p = 0.010). Immunohistochemical analysis indicated positive expression of S-phase kinase-associated protein 2 in 16/29 nasopharyngeal tissue samples (55 per cent), of cyclin E in 13/29 samples (45 per cent) and of p27 protein in 17/29 (59 per cent) samples. CONCLUSIONS: Overexpression of cyclin E messenger ribonucleic acid showed an adverse prognostic significance, correlating with an advanced stage of nasopharyngeal carcinoma and a low overall survival rate.