Expression of 14-3-3σ in cervical squamous cell carcinomas: Relationship with clinical outcome

Abstract

14-3-3 sigma (σ) sequesters the cdc2-cyclin B1 complex in the cytoplasm resulting in G2 arrest. Inactivation and reduced expression of 14-3-3σ have been reported in a varity of cancers. In the present study, we investigated the expression of 14-3-3σ in a series of 297 cervical squamous cell carcinoma (SCC) to clarify the prognostic value. Using immunohistochemical methods we found high levels of 14-3-3σ protein in cytoplasm of 143 (48.1%), in nucleus of 113 (38.0%) and in both cytoplasm and nucleus of 147 (49.5%) cases, whereas, low levels were present in cytoplasm of 154 (51.9%), in nucleus of 184 (62.0%) and in both cytoplasm and nucleus of 150 (50.5%) cases. Levels of 14-3-3σ mRNA measured by reverse-transcription polymerase chain reaction (RT-PCR) and 14-3-3σ protein were not significant associated. 14-3-3σ expression in cytoplasm, nuclear and cytoplasm/ nuclear were not significantly correlated to disease-specific survival or disease-free survival. In conclusion, reduced expression of 14-3-3σ protein in the cytoplasm and shuttle of 14-3-3σ protein into the nucleus in a relatively high number of cases indicate that 14-3-3σ may be important in the carcinogenesis of cervical SCCs by two different mechanisms; reduction and nuclear translocation of 14-3-3σ protein. Furthermore, the non-significant correlation between expression levels of 14-3-3σ mRNA and protein support a post-transcriptional regulation in cervical SCCs. The protein has no prognostic value in cervical cancers.