A considerable part of many eukaryotic genomes consists of repetitive sequences derived from transposable elements (TEs). TEs are genetic elements that have, or once had, the capability to hop around their host genomes. Through their mobility, they threaten host genomic stability; consistently, uncontrolled TE transposition has been linked to infertility and to diseases such as cancer, hemophilia, and neurodegeneration (McCullers and Steiniger, 2017). An increasing body of evidence shows that TE expression is elevated in cancer, and accumulation of TE transcripts and extrachromosomal DNA derived from TEs has been shown to trigger an innate immune response (Cuellar et al., 2017;