In addition, we found that mutations in POLD1, encoding the DNA polymerase delta 1 that is a key protein for ensuring the replicative fidelity of DNA, were also associated with an increase in overall toxicity risk (pneumonitis and/or esophagitis, 77.8% vs. 38.9%, OR=5.4 [95% CI, 0.97-55.7], P=0.03, Figure 7D). Here, POLD1 is linked to pneumonitis.