XRCC3 and cancer: Since the two homologous recombination genes XRCC3 and RAD51B were identified in the cross-validation and also found to be differentially methylated in all cancer types, they were further analyzed for correlations with a broad panel of immune-associated genes, including checkpoint molecules, checkpoint ligands, interferon gamma, T-cell markers and HLA-1 associated genes (Figure 6, Supplementary Figure S3 and S7).