The Relationship Between Homologous Recombination Repair and the Sensitivity of Human Epidermis to the Size of Daily Doses Over a 5-Week Course of Breast Radiotherapy

Cell cycle arrest in S/G2 phase in the basal epidermis after a 5-week course of radiotherapy is associated with greater use of homologous recombination for repairing DSB. The high fidelity of homologous recombination, which is independent of DNA damage levels, may explain the low-fractionation sensitivity of tissues with high-proliferative indices, including self-renewing normal tissues and many cancers.