Expression of CXCR4 indicates poor prognosis in patients with clear cell carcinoma of the ovary

Recent reports have shown that CXCR4 is expressed in various solid tumors and is involved in tumor development and metastasis. We examined the distribution and expression of this molecule in clear cell carcinoma of the ovary to elucidate its clinical significance. Paraffin sections from clear cell carcinoma of the ovary tissues (n = 42) were immunostained with CXCR4 antibody, and the staining intensities were evaluated. The clinicopathologic factors examined were age, FIGO (International Federation of Gynecology and Obstetrics) staging, preoperative value of cancer antigen 125 test, and residual tumor after cytoreductive surgery. Overall survival and progression-free survival were evaluated using the Kaplan-Meier method, and multivariate analysis was completed using Cox proportional hazards analysis. Of the 42 carcinomas, lower level CXCR4 immunoexpression was observed in 21 cases (50.0%) (CXCR4 ^low group); and higher level immunoexpression, in 21 cases (50.0%) (CXCR4 ^high group). Five-year overall survival was significantly poorer in the CXCR4 ^high group than in the CXCR4 ^low group (overall survival, CXCR4 ^low group [90.2%], CXCR4 ^high group [50.3%]; P =.0002). In addition, CXCR4 ^high immunoexpression significantly predicted a poorer progression-free survival when compared with lower expression (5-year progression-free survival, CXCR4 ^low group [90.5%], CXCR4 ^high group [36.2%]; P <.0001). Furthermore, multivariate analyses including the age, preoperative cancer antigen 125 test value, FIGO stage, and CXCR4 expressions revealed that CXCR4 ^high expression was an independent prognostic factor for poorer overall survival and progression-free survival of patients with clear cell carcinoma of the ovary (overall survival, P =.0011; progression-free survival, P =.0008, respectively). Our current study suggested that the assessment of CXCR4 immunoreactivity may be a useful prognostic indicator and that CXCR4 may play a critical role in the progression of clear cell carcinoma of the ovary.