BRCA1 and Fanconi anemia: Bortezomib and other proteasome inhibitors are shown to delay or inhibit various stages of HR and the Fanconi anemia pathway.22, 23 We argued that, if sensitization to bortezomib is due to the role of BRCA1 in HR, knockdown of BRCA2, which is even more directly involved in HR, should produce the same effect.