E-cadherin and alpha-, beta-, and gamma-catenin protein expression is up-regulated in ovarian carcinoma cells in serous effusions

The aims of this study were firstly, to investigate the expression of E-cad herin complex proteins in ovarian carcinoma cells in serous effusions and i n primary and metastatic lesions; and secondly to study the value of these four proteins and calretinin, a mesothelial marker, in the differential dia gnosis of ovarian carcinoma cells from reactive mesothelial cells in effusi ons. Sixty-seven malignant effusions and 97 corresponding primary (n = 36) and metastatic (n = 61) lesions were immunohistochemically stained for E-ca dherin and alpha-, beta-, and gamma -catenin. Staining extent and intensity were scored. Effusion specimens were additionally analysed for calretinin immunoreactivity. Membrane immunoreactivity for E-cadherin and alpha-, beta -, and gamma -catenin was detected on carcinoma cells in the majority of th e effusions, but rarely on reactive mesothelial cells (p < 0.001 for all ma rkers). Calretinin immunoreactivity was confined to mesothelial cells (p < 0.001). An association was seen between E-cadherin and alpha -catenin expre ssion, in both effusions and solid tumours, and for beta -catenin in solid tumours (range p < 0.001 to p = 0.014). Up-regulation of all four cadherin complex proteins was seen in carcinoma cells in effusions, when compared wi th corresponding primary tumours (range p < 0.001 to p = 0.028). As with ef fusions, metastatic lesions showed up-regulation of alpha-, beta-, and gamm a -catenin when compared with primary carcinomas (p = 0.002-0.015). Carcino ma cells in effusions showed in addition elevated levels of E-cadherin when compared with metastatic lesions (p < 0.001). Staining results in effusion s showed no association with effusion site, tumour type or histological gra de. Immunoblotting on 29 malignant effusions confirmed the presence of all four proteins in the majority of samples and coprecipitation of E-cadherin and <beta>-catenin was seen in ten specimens examined. E-cadherin complex p roteins are widely expressed in ovarian carcinoma cells. Together with calr etinin, they form a powerful battery of markers for the cytological diagnos is of carcinoma cells in effusions. The up-regulation of E-cadherin complex proteins in serous effusions and metastatic lesions may mark an early meta static phenotype and possibly mediates survival of tumour cells at these si tes through the inhibition of apoptosis. Copyright (C) 2000 John Wiley & So ns, Ltd.