Studies on RNF126 in triple-negative breast cancer (TNBC) show that it enhances DNA exonuclease activity by physically binding to the MRE11-RAD50-NBS1 (MRN) complex and ubiquitinating MRE11 at specific amino acid sites, thereby promoting homologous recombination repair (HR) and maintaining genome stability [20]. The gene discussed is MRE11; the disease is triple-negative breast carcinoma.