This finding in HCC, in contrast to that in melanoma, is of great importance, the different roles of apoE2 and apoE4 in HCC and melanoma may suggest that the organ difference of tumorigenesis results in different immune mechanisms, which may partly account for the reasons why it is currently difficult to construct a widely accepted systematic theory in the immune escape of cancers. This evidence concerns the gene APOE and hepatocellular carcinoma.