ATM and cancer: Irradiation (IR) 6 Gy with analysis of P-ATM-S1981 at 0.5–1 h has previously been used by other groups to study ATM activation in human cancer cells.27,29–31 In MIA PaCa-2, low nanomolar concentrations of AZD0156 (≥10 nM) successfully abrogated IR-induced ATM auto-phosphorylation (Fig. 1a).