Expression of Cell Cycle Proteins in Ovarian Carcinoma Cells in Serous Effusions—Biological and Prognostic Implications

Abstract

Objective. The aim of this study was to investigate the expression of cell cycle proteins in ovarian carcinoma cells in serous effusions and respective solid tumors.Methods. Fifty-five malignant effusions and 38 tumors (20 primary, 18 metastatic) were immunohistochemically stained for cyclin A, p27kip1, and Ki-67. Staining extent (0–100% cells) and intensity (0–3 scale) were scored. Cyclin A and p27kip1 expression was additionally studied in 29 malignant effusions using immunoblotting. Immunohistochemistry results in effusions were evaluated for possible association with clinicopathologic parameters.Results. Nuclear immunoreactivity for all markers was detected on carcinoma cells in the majority of effusions using immunohistochemistry. Similarly, immunoblotting showed the presence of cyclin A and p27kip1 in 29/29 and 25/29 specimens, respectively. Intense (3) immunoreactivity for Ki-67 was detected more often in peritoneal effusions, compared with those of pleural location (P = 0.036). Staining in primary and metastatic lesions was generally comparable to that of tumor cells in effusions. Staining for p27kip1 was more diffuse in effusion specimens obtained prior to the institution of chemotherapy (P = 0.042). In an analysis of all effusions, an association was observed between the number of cells that were immunoreactive for Ki-67, cyclin A, and p27kip1 (cyclin A–Ki-67: P = 0.008; p27kip1–Ki-67: P = 0.019; cyclin A–p27kip1: P = 0.032). In survival analysis, the presence of more diffuse (P = 0.042) and intense (P = 0.019) staining for cyclin A correlated with prolonged overall survival.Conclusions. The expression of the studied cell cycle markers does not differ markedly between ovarian carcinoma cells in the pleural and peritoneal cavity, supporting our previous studies of several metastasis-associated molecules. The presence of cyclin-A-positive cell populations is associated with a more favorable disease outcome, possibly due to the targeting of proliferating cells by chemotherapeutic agents. However, the decline in the fraction of p27kip1-positive cells in posttreatment specimens may point to additional mechanisms involved in this selection.