MRC1 and non-small cell lung carcinoma: To test our hypothesis that mutations in these single DNA repair genes can serve as biomarkers for identifying NSCLC patients with higher mutational burden and increased TILs, we analyzed tumors specifically containing mutations in the HR pathway, the MMR pathway, or POLE. In each grouping, tumors with DNA repair deficiencies displayed significantly increased mutation counts (and a trending further increased mutation count with multiple HR and MMR genes mutated) (Figure 3A.i, 3B.i, 3C.i).