However, a part of our results are in agreement with a recent study by Ok et al. who reported that emodin indeed can inhibit the migration and invasion of prostate and lung cancer cells by downregulating the expression of CXCR4, although the potential in vivo effects of emodin on metastasis and CXCR4 expression was not investigated by this group [33]. Here, CXCR4 is linked to lung cancer.