CHEK2 and neoplasm: In seven additional high CNV burden cases with IHC data, we identified homozygous deletions of CHEK2, BRIP1, and DCLRE1C and mutations in BRCA1, FBXW7, PRKDC, and ALKBH5. Two of these—BRCA1mut and PRKDCQ75R—had high PD-L1 expression on the surface of tumor cells whereas the other three had rare or low expression on non-tumor cells.