Unlike the down-regulation and anti-carcinogenic effect of ACP6 reported in esophageal squamous cell carcinoma and ovarian cancer [17, 18], overexpression of ACP6 in HCC and the positive relationships between ACP6 expression and clinical indicators of the progression of HCC discovered from the present study implied that ACP6 might play diverse roles in different human cancers. This evidence concerns the gene ACP6 and esophageal squamous cell carcinoma.