CD44 expression indicates favorable prognosis in epithelial ovarian cancer.

Abstract

The purpose of this study was to investigate the expression and prognostic significance of CD44 in epithelial ovarian cancer. We analyzed the expression of CD44 by immunohistochemistry in 307 epithelial ovarian cancers and evaluated its relation to hyaluronan, clinicopathological factors, and prognosis. Fifty-one percent of the tumors had a high proportion of CD44-positive cells (i.e., >/==" BORDER="0">10%), and this high CD44 expression was significantly associated with cancer cell-associated hyaluronan, well-differentiated tumor, mucinous histological type, and early stage of the tumor. High CD44 expression predicted better 5-year overall survival (50% versus 22%) and recurrence-free survival (70% versus 34%) in the univariate analyses (P < 0.00005 for both). In the Cox multivariate analyses, the independent predictors of overall survival at 5 years were primary residual tumor (P < 0.0005), International Federation of Gynecologists and Obstetricians (FIGO) stage (P = 0.001), histological grade (P = 0.014), adjuvant chemotherapy (P = 0.004), and stromal hyaluronan level (P < 0.0005), but not CD44. However, the expression of CD44 (P = 0.04) and stromal hyaluronan (P = 0.005) were both independent predictors of recurrence-free survival at 5 years, together with the size of the primary residual tumor (P < 0.0005) and histological type (P = 0.043). The relatively frequent ectopic expression of CD44 on ovarian cancer cells is thus related to well-differentiated, early-stage tumor and long survival of the patients. Thus, whereas CD44-expressing cancer cells may adhere and implant to the hyaluronan-positive mesothelium, at least in model systems, high expression of CD44 in the tumor does not bring about an unfavorable prognosis.