XRCC4 and Fanconi anemia: Proteins other than BRCA2 implicated in homologous recombination or the Fanconi anemia repair pathway, like BRCA1, RAD51, PALB2, XRCC3, FANCI, or FANCD2, were at most modestly affected (Figure 4A), as were non-homologous end joining proteins like KU80, KU70, and XRCC4 (Figure 4B).