ATR and cancer: Activation of extraembryonic features in response to ATR in early stages of cellular transformation could be a major outcome of RS induced by oncogene activity in cancer cells and would provide an additional rationale for the potent tumor suppressive effect of ATR inhibitors (Costanzo et al., 2018; Bartek et al., 2012; Bartkova et al., 2005; Dobbelstein and Sørensen, 2015; Macheret and Halazonetis, 2015; Nieto-Soler et al., 2016).