For example, a negative selection RNAi screen from over 10,000 genes in pancreatic cancer BxPC-3 cells identified Rad17, an important regulator of the ATR-Chk1 DDR pathway (Zou et al., 2002; Cimprich and Cortez, 2008), as the most significant synthetic lethal target with GEM treatment, and validation experiments showed that Rad17-KD sensitizes pancreatic cancer cells including BxPC-3, MiaPaCa2, and JoPaca-1 to GEM (Fredebohm et al., 2013). This evidence concerns the gene CHEK1 and pancreatic neoplasm.