TACSTD2 and hepatocellular carcinoma: Another study, focused on genome-wide DNA methylation in various regions of the genome in HCC and adjacent nontumorous tissues, found the TACSTD2 promoter locus to be hypermethylated in HCC samples [49], which is consistent with downregulation of this gene and could explain the very low expression of TACSTD2 detected in our HCC samples.