However, it must be noted that hypermethylation of PRC2 targets is not exclusive to stem cells; indeed, researchers have reported that in somatic cells, a subset of polycomb targets exhibit a clear trend toward hypermethylation with age, independently of disease state, sex, or cell type (upon comparison of blood, ovarian cancer, cervix and lung tissues) ( Christensen et al. , 2009 ; Teschendorff et al. , 2010 ).
1
—
—