CHEK1 and Bloom syndrome: Elevated expression of KLF5 promotes the expression of key HRR pathway genes, including RAD51, checkpoint kinase 1 (CHEK1), RAD54 like (RAD54L), essential meiotic structure-specific endonuclease 1 (EME1), and Bloom syndrome (BLM), thereby reversing the HRR suppression mediated by PARPi.