Expression of 14-3-3 sigma and eta proteins is unrelated to survival in metastatic high-grade serous carcinoma

The objective of this study was to analyze the expression and clinical role of 14-3-3 family proteins in high-grade serous carcinoma (HGSC). Protein expression of 14-3-3 sigma (14-3-3 sigma) and 14-3-3 eta (14-3-3) by immunohistochemistry was studied in 298 HGSC specimens (249 peritoneal, 49 pleural) and was analyzed for association with clinicopathologic parameters, chemoresponse and survival. The 14-3-3 sigma protein was diffusely (>75% of cells) expressed in 100% of carcinomas in analysis of a pilot series and was therefore not further analyzed. The 14-3-3 protein was expressed to a variable extent in 260/298 (87%) effusions. Higher 14-3-3 protein expression was significantly related to higher CA 125 levels at diagnosis (p=0.004), but was unrelated to other clinicopathologic parameters, chemoresponse or survival. Analysis of the association between 14-3-3 and previously studied proteins regulating mitosis showed positive association with class III -tubulin expression (p=0.025). The present study documents frequent expression of 14-3-3 sigma and 14-3-3 in HGSC effusions, but does not support a role for these proteins as prognostic markers or predictors of chemotherapy response in metastatic HGSC.