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 (14‐3‐3σ) and 14‐3‐3 eta (14‐3‐3η) by immunohistochemistry was studied in 298 HGSC specimens (249 peritoneal, 49 pleural) and was analyzed for association with clinicopathologic parameters, chemoresponse and survival. The 14‐3‐3σ protein was diffusely (>75% of cells) expressed in 100% of carcinomas in analysis of a pilot series and was therefore not further analyzed. The 14‐3‐3η protein was expressed to a variable extent in 260/298 (87%) effusions. Higher 14‐3‐3η 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 14‐3‐3η and previously studied proteins regulating mitosis showed positive association with class III β‐tubulin expression (p = 0.025). The present study documents frequent expression of 14‐3‐3σ and 14‐3‐3η in HGSC effusions, but does not support a role for these proteins as prognostic markers or predictors of chemotherapy response in metastatic HGSC.