CHEK1 and neoplasm: With these reduced doses, we observed on-target inhibition of WEE1 indicated by a decrease in phosphorylation of CDC2 at Tyr15 as well as increase in DNA damage signalling as indicated by the phosphorylation of CHK1 at Ser345 in the AZD1775 monotherapy and combination treatment groups compared with the vehicle treatment groups of the AT3OVA model, similar to that of the AT3 tumours treated with higher doses (Supplementary Fig. 3c).