In pembrolizumab treated non-small cell lung cancers, higher burden of nonsynonymous mutations was associated with increased clinical response and progression-free survival (PFS), and responders with the greatest number of mutations contained mutations in the DNA repair genes POLD1, POLE, MSH2, PRKDC, RAD17, BRCA2, RAD51C, and/or LIG3. Also within this study, clinical response and increased PFS correlated with a higher burden of identified candidate neo-antigens, and a neo-antigen-specific T cell population was identified in one responder that correlated with tumor regression [47]. The gene discussed is POLD1; the disease is neoplasm.