CCR4 and hepatocellular carcinoma: Besides, literature reports that CCR4 can aggravate hepatocellular carcinoma malignancy and facilitate hepatocellular carcinoma cell metastasis via activating ERK/AKT/MMP2 pathway [24] and CCR4 can promote colorectal cancer metastasis via activating ERK/NF-κB/MMP13 pathway [23].