Interestingly, the observed S phase impairment along with caspase 3-mediated apoptosis in POLD1-deficient colorectal cancer cells upon AZD6738 treatment has similarly been demonstrated in ATM-dysfunctional gastric cancer cells upon AZD6738 treatment, supporting the known synthetically lethal relationship between ATR and ATM27. Here, POLD1 is linked to gastric cancer.