APC and hepatocellular carcinoma: Together with the results of our recent studies, which showed that strand-biased methylation of the APC gene is present in liver and that methylation of only the sense strand is specific for HCC [33], these results highlight the importance of the locations of CpG methylation of a given marker for clinical applications, particularly in liver cancer, since both of the methylation markers we studied exhibited a liver-specific DNA methylation pattern when compared to the other 11 normal tissues examined.