Additionally, natural substances isolated from plants have demonstrated cytotoxic activity against cancer cell lines, as demonstrated in a study where they found that the natural flavonoid fisetin induced apoptosis of HeLa cells by triggering the activation of caspases-3 and -8 and the cleavage-PARP, resulting in the induction of apoptosis [34, 35]. The gene discussed is CASP3; the disease is cancer.