For this aim, we tested the effect of chaetocin on 53BP1 foci induced by doxorubicin, which targets topoisomerase II, or olaparib, a specific PARP1 inhibitor that is used in cancer treatment by itself or in combination with other drugs as a form of synthetic lethality (Dungey et al., 2009; Tewari et al., 2015; Ramakrishnan Geethakumari et al., 2017; Robson et al., 2017; Chabanon et al., 2019). Here, PARP1 is linked to cancer.