ATM and Fanconi anemia: Typically, loss of function mutations and epigenetic modification in BRCA1/2 or genes encoding other fundamental players in the HRR pathway (Table 1), such as ATM, BARD1, BRIP1, H2AX, MRE11, PALB2, RAD51, RAD51C/D, RPA, and Fanconi Anemia Complementation Group genes, have been identified as important causative factors of HRD in HGSOC [15].