We found that the intermediate isolates not only showed lower DLX susceptibility compared to the recA::Tn mutant, but also had reduced susceptibility against three other DNA damaging agents, a different fluoroquinolone ciprofloxacin (CPX) [25,26], the anti-cancer drug doxorubicin (DOXO) [27] and the chemotherapeutic mitomycin C (MMC) [28], compared to the hyper-sensitive recA::Tn mutant (Fig 2A). This evidence concerns the gene RAD51 and cancer.