Possible models to explain the association between LINE-1 hypomethylation and CRC progression. (A) In the prevailing model, LINE-1 methylation decreases progressively during CRC progression. (B) In an alternate model, LINE-1 methylation is stable during CRC progression and the time of diagnosis may be the critical factor that determines the observed association between methylation level and disease stage. In both models, the solid line shows a change of LINE-1 methylation during CRC progression and the arrowhead indicates the time of diagnosis, surgery and sample collection.
Matsunoki et al. BMC Cancer 2012 12:574 doi:10.1186/1471-2407-12-574