Figure 2.

CGI methylator phenotype (CIMP) and ‘pseudoCIMP.’ Open rectangles show unmethylated CGI, and closed rectangles show methylated CGI. In cancer cells (shown in pink or red) with intrinsic defects (a), aberrant methylation keeps occurring. After several clonal selections during multistep carcinogenesis, all cancer cells come to have methylation of multiple CGI. In contrast, if a cancer cell is derived from a precursor cell with methylation of multiple CGI (b), cancer cells derived from it will also display methylation of multiple CGI.