Compared to control exosomes derived from HEK293 epithelial cell line, experimental exosomes derived from SKOV3 cancer cells carrying CRISPR/Cas9 not only allowed efficient inhibition of poly (ADP-ribose) polymerase-1 (PARP-1)-induced apoptosis in ovarian cancer but also preferentially accumulated in the lesion in a SKOV3 xenograft mouse model, providing tropism-dependent targeting [64]. This evidence concerns the gene PARP1 and cancer.