At Repron, we are developing an innovative strategy to inhibit the activity of oncogenes at the basis of tumor malignancy through the use of engineered synthetic factors. Oncogenic transcription factors activate thousands of target genes that, regulating processes like cell proliferation and invasiveness, make the cancer cells dangerous. By rational engineering of these factors, we exploit the natural binding ability to deliver repressive activity, instead of activation to their targets. Substituting the domain responsible for the activation with others featuring epigenetic inhibitory capabilities, we obtained Epigenetic Silencer Factors, that, once delivered in the cancer cells, are able to switch-off key genes for tumorigenesis. Our purpose is to provide solutions for those solid tumor cases in which the radical removal is not possible and metastasizing or recurrence is highly probable. Indeed, the delivery of Epigenetic Silencing Factors could intercept and eliminate either the remaining tumor cells at the primary site or the micro metastasis in target organs.