Fig. 1
From: Transposable elements as essential elements in the control of gene expression
TEs are regulated in both healthy and cancerous cells. Epigenetic changes such as DNA methylation, histone modification, and non-coding RNA (eg cirRNA, miRNA, and lncRNA) inhibit the function of TEs in healthy cells (left panel). During cellular transformation, hypomethylation with increased S-Adenosyl methionine (SAM), various histone modifications (like methylation and acetylation), and oncogenic non-coding RNAs, which inhibit the expression of tumor suppressor genes (TSGs), all contribute to the loss of repressive signals and the uncontrolled production of TEs in cancer cells (right panel). DNA breakdown, mutations, and genomic instability result from all these (arrows indicate the increased activity, cross circle indicates inhibition; ( +) sign indicates increment, (–) sign indicates decrement, and cross sign indicates inhibition) [26]