HB gene mutations are simple, and whole-exon sequencing shows that there are only 2.9 mutations per HB tumor on average [13], which is much lower than 35–66 mutations per tumor in liver cancer [14–16], indicating that HBs are not only caused by the accumulation of gene mutations; in addition, most HBs occur in children, suggesting that epigenetic mechanisms that control development play an important role in the occurrence and development of HB. This evidence concerns the gene GSTM1 and neoplasm.