PRDM9 and pachyonychia congenita: For example, the main histone methyltransferase, responsible for H3K27 (the lysine residue at N-terminal position 27 of histone 3) trimethylation and the aberrant silencing of multiple tumor suppressor genes, namely the enhancer of zeste homolog 2 (EZH2), has been shown to be overexpressed in PC cells and hyperphosphorylated by several kinases, such as Akt, and thus promotes the expression of several critical oncogenes and induces PC metastasis [16,211].