Comparative study of paired box gene 8, cytokeratin 7, and cytokeratin 20 in differentiating the ovarian from nonovarian carcinoma cells in peritoneal effusions

Abstract

Background In female patients, ovarian carcinoma is considered a common cause of malignant peritoneal effusions that shows a good response to chemotherapy, an issue that mandates quick and accurate diagnosis of those cases. PAX8 is a cell lineage factor that plays a crucial role in the morphogenesis of the kidney, thyroid gland, and Mullerian system. It is expressed in 95–100% of ovarian carcinomas in tissue sections. Recently, it was suggested as a potential marker for the diagnosis of ovarian carcinomas in effusions. Aim This study aimed at assessing the role of CK7, CK20, and PAX8 in differentiating ovarian from nonovarian carcinomas in peritoneal effusions. Patients and methods Immunocytochemical evaluation of CK7, CK20, and PAX8 expression in 40 cell blocks of malignant peritoneal effusion samples was carried out. In addition, the assessment of PAX8 level using double-antibody sandwich enzyme-linked immunosorbent assay technique in the serum of the included cases was also carried out. Results Of the studied 40 cases, 21 (52.5%) proved to be ovarian carcinomas, whereas 19 (47.5%) were nonovarian. Diffuse CK7 expression (scores 3, 4) was significantly detected more frequently in effusions from ovarian than from nonovarian carcinomas. In contrast, CK20 expression tended to be more prevalent in effusions of nonovarian than in those of ovarian origin; however, this was statistically insignificant. PAX8 expression was significantly more frequent in effusions from ovarian carcinomas than from nonovarian carcinomas. Sensitivity and specificity of PAX8 in the diagnosis of ovarian carcinoma was higher than that of CK7, while a combination of both CK7 and PAX8 immune scores using a generated regression equation was the most specific. In contrast, serum PAX8 level was statistically higher in ovarian more than in nonovarian carcinoma cases. Conclusion PAX8 is a useful immune marker for the diagnosis of ovarian carcinoma in peritoneal effusions. However, the combination of both CK7 and PAX8 using a generated regression equation increases the specificity of diagnosis. PAX8 serum level is a potential serum marker in diagnosing ovarian carcinomas.