PARP inhibitors are a class of drugs that block the enzyme poly (ADP-ribose) polymerase (PARP), which is involved in DNA repair, thereby exploiting the concept of synthetic lethality to selectively kill cancer cells with existing DNA repair deficiencies, such as those with BRCA mutations. These inhibitors have shown promise in treating certain types of cancers, including ovarian, breast, and prostate cancers, by preventing cancer cells from repairing their DNA and ultimately leading to cell death.