Loss of hATM (−/−) was concomitantly associated with low BRCA1 and BRCA2 protein expression in both the hATM (−/−) DLD-1 cell line and PARPi-sensitive ATM mutant NSCLC PDX models, suggesting a downstream effect on the impairment of HR-mediated DNA checkpoint signaling. Here, ATM is linked to non-small cell lung carcinoma.