PRDM9 and posterior cortical atrophy: Currently there is no study on the role of EZH1 in H3K27 methylation in PCa cells, but it would be plausible to postulate that when EZH2 is phosphorylated at Ser21 and preferentially associated with Stat3 in chemoresistant PCa cells, EZH1 (and possibly other histone methyltransferases) can complement the canonical EZH2 function and maintain the H3K27Me3 mark.