CXCR4 and lung cancer: The HR from 7 studies including early resected lung cancer (stage I-III) patients and 1 study including metastatic lung cancer (stage IV) patients showed that increased CXCR4 expression predicted poor OS (HR 1.62, 95% CI 1.32–1.98, P < 0.001, I2 = 48.5%; HR 1.67, 95% CI 1.16–2.38).