Moreover, the knockdown of RAD51, BRCA1 (breast cancer 1), and the RAD51 paralog XRCC3 (X-ray repair cross complementing 3) prevented the repair of the O6mG-induced DSBs leading to cell sensitization, while RAD51-CRISPR activation led to TMZ resistance [91,92,93]. The gene discussed is XRCC3; the disease is breast cancer.