A recent study led by Professor Lisa Wiesmüller at Ulm University Hospital has unveiled a peptide that could prevent DNA breaks associated with treatment-induced leukemia. Secondary leukemias arise from DNA damage caused by chemotherapy or radiotherapy, particularly in the MLL/KMT2A gene region. The enzyme endonuclease G (EndoG) is known to trigger these breaks. The researchers discovered that a specific section of the DNA repair protein Ku80 acts as a natural inhibitor of EndoG. They synthesized peptides that mimic this inhibitory effect, successfully reducing DNA alterations linked to leukemia in cell models. Unlike previous approaches that inhibited EndoG entirely, compromising chemotherapy's effectiveness, this new peptide selectively targets harmful interactions. While still in the early stages, these peptides represent a promising avenue for developing targeted therapies to mitigate the long-term effects of cancer treatments. The findings were published in Nature Communications, highlighting the potential for future research to create more effective therapeutic interventions.