Figure 2.

DNA methylation in normal and cancer cells. In normal cells, most repetitive sequences are methylated, whereas the promoters of tumor suppressor genes (TSG) stay unmethylated, remaining active and leading to gene expression (green check mark). Contrarily, in cancer cells, repetitive sequences become unmethylated and active, contributing to genomic instability, and TSG promoters become methylated, inactivating these genes and promoting cell aggressiveness and escape (red cross mark).