After intravenous injection of exosomes from SKOV3 human ovarian cancer cells (SKOV3-Exos) loaded with CRISPR/Cas9, they target and accumulate in SKOV3 tumors, inhibiting PARP-1 gene expression and subsequently inducing apoptosis of ovarian cancer cells (Kim et al., 2017). The gene discussed is PARP1; the disease is ovarian carcinoma.