Immunoexpression of PAX 8 in endometrial cancer: Relation to high grade carcinoma and p53

PAX 8 is a crucial transcription factor for organogenesis of the thyroid gland, kidney, and the Müllerian system and plays an essential role in cell proliferation. The purpose of this study was to evaluate the association between p53 and PAX 8 expression and the clinical value of PAX 8 in endometrial carcinoma. We detected 106 consecutive patients with primary endometrial carcinoma (type I/endometrioid, n=84; type II/non-endometrioid, n=20; rare subtypes, n=2) who were treated at our institution between 1999 and 2009. Out of the 106 patients 97 cases were eligible for further investigations. PAX 8 and p53 expression were assessed using immunohistochemistry from paraffin-embedded tissue blocks. Results were correlated with clinical data. PAX 8 immunoreaction was found in 70 of 97 (72.1%) patients, including 56 of 77 (72.7%) endometrioid carcinomas and 13 of 18 (72.2%) type II carcinomas. A positive correlation was observed between PAX 8 and p53 expression (p=0.0005), histological type (p=0.04) and histological grade (p=0.02). No association was found between PAX 8 expression and tumor stage, vascular space involvement, lymph node involvement, and patients' age. Furthermore, using univariate and multivariate analyses, no statistically significant relationship could be evaluated between patient survival data and PAX 8 expression. PAX 8 is expressed in the vast majority of endometrial carcinomas both of endometrioid and non endometrioid type. PAX 8 overexpression correlates with p53 expression and high-grade endometrial carcinomas but seems not to be useful as a prognostic parameter.