Our work has yielded an important sum of novel information on how some 350 human KZFPs recognize their TE targets, how these KZFPs functionally diversified throughout evolution, how they act during early embryogenesis to tame the regulatory power of TEs in order to facilitate its domestication for the benefit of the host, and how TEs and their KZFP controllers have fed higher vertebrates with cis- and trans-acting regulatory sequences that likely influence all aspects of human biology. Turning to the involvement of this system in human pathologies, we have discovered TE-based biomarkers of great potential value for precision oncology, and unveiled how the the genomic surveillance exerted by KZFPs is perverted in the context of cancer cells, where it confers protection against the genotoxic consequences of pro-oncogenic epigenetic changes. These results reveal an important role for a family of largely species-restricted proteins in the pathogenesis of human cancer, and also point to new avenues for therapeutic intervention.