RAD51 and breast cancer: To investigate the impact of RAD51 inhibitor on CPT-induced genomic instability, esophageal adenocarcinoma (OE19 and FLO-1), colon (HCT116) and breast cancer (MCF7) cell lines were treated with RAD51 inhibitor (RI-1), camptothecin (CPT; a DNA breaking agent) or combination of both for 48 h and the impact on micronuclei (a marker of genomic instability) evaluated using flow cytometry.