Pair Box 8 (PAX8) protein expression in high grade, late stage (stages III and IV) ovarian serous carcinoma

ObjectivesPair-Box 8 (PAX8) is a transcription factor which has been found to be overexpressed in ovarian serous carcinoma (OSC). Silencing PAX8 by using shRNA led to a drop in cell viability in ovarian cancer cell lines, suggesting its use as a targeted therapeutic agent. The prognostic value of PAX8 in OSC is still widely unknown. The aim of this study was to evaluate PAX8 as a prognostic biomarker in patients with advanced stage OSC.MethodsPAX8 was evaluated using immunohistochemistry on a tissue microarray of 148 OSC and the expression was correlated to the following clinico-pathologic variables; age of diagnosis, tumor stage, optimal debulking, recurrence free survival (RFS) and overall survival (OS).ResultsWe found that PAX8 was expressed in 61% of cases. There was no association between PAX8 and tumor stage, optimal debulking and disease recurrence. In addition, PAX8 failed to have a predictive value in disease outcome.ConclusionDespite showing that PAX8 protein is not a useful predictive marker in patients with high grade, advanced stage OSC, its overexpression in a large number of these cases makes the inhibition of PAX8 a very attractive targeted therapy.

► PAX8 protein is expressed in a vast majority of high grade, late stage, ovarian serous carcinoma.
► PAX8 was not associated with tumor stage, optimal debulking and recurrence.
► Due to its overexpression in high grade, late stage ovarian serous carcinoma, inhibition of PAX8 is an attractive targeted therapy.