CXCR4 and ovarian cancer: Besides, subgroup analyses according to the proportion of stage III-IV patients showed that high CXCR4 expression was also related significantly with poor prognosis in studies with more stage III–IV patients (pooled ES, 4.13; 95% CI: 2.15–7.92; I2 = 8.9%), suggesting that high expression of CXCR4 predicts poor prognosis in patients with advanced ovarian cancer.