“…Although the current view in the field is that ATM and ATR signaling inhibits tumor progression rather than promoting cancer (Bartkova et al, 2006;Gorgoulis et al, 2005;Halazonetis et al, 2008), there has been a number of recent reports of overexpression of ATM or ATR, or of activation of the downstream pathways in different cancers (Albiges et al, 2014;Bhatia et al, 2013;Hoglund et al, 2011;Mahajan et al, 2012;Sarmento et al, 2015;Tho et al, 2012;Vadnais et al, 2012;Verlinden et al, 2007;Xu et al, 2013) (see poster). Of note, the addition of an extra allele of Chk1 has even been found to promote Ras-or E1A-mediated transformation more efficiently in comparison to such transformation of wild-type littermates (Lopez-Contreras et al, 2012), suggesting that the ATR-Chk1 axis has a pro-malignant transformation role.…”