CHEK1 and cancer: Likewise, SLFN11 low pan-cancer cell lines globally benefitted from the combination of SN-38 with different inhibitors of the CHK kinase (SRA737, which targets preferentially CHK1, or prexasertib (a double CHK1/2i) (left panels of Fig. 6c and Supplementary Fig. S8B, respectively) or WEE1i (Fig. 6c, right), but not by combination with olaparib (Supplementary Fig. S8B, right).