TP53 and breast cancer: Interestingly, UCN-01 was affirmed to potentiate camptothecin (CPT)-induced cytotoxicity in two human BC cell lines with a mutated p53 gene via modulating CPT-activated S and G2 checkpoints, which indicated the potential efficacy of combined therapy with UCN-01 and topoisomerase I inhibitors in BCs with an aberrant p53 gene [90].