The BRCA2 gene is known to play a crucial role in repairing and stabilizing DNA during cell replication. Mutations to the gene, however, can impair the DNA repair process and increase the risk of tumor formation. The researchers found, to their surprise, that when PARP inhibitors inadvertently trap PARP1 proteins on DNA, the PARP1 proteins can destabilize repair complexes and hinder DNA repair processes initiated by RAD51. Remarkably, Jensen said, the BRCA2 gene effectively shields these complexes, maintaining the integrity and function of DNA repair pathways. “Cancer cells can somehow tolerate the loss of the BRCA2 pathway, but when the PARP1 protein is inhibited, they die,” he said.