and it has been demonstrated in mice that these inhibitors can both prevent BRCA1/2-deficient xenografts from becoming tumors and eradicate tumors having previously formed from BRCA1/2-deficient xenografts. Application to cancer therapy PARP1 inhibitors are being tested for effectiveness in cancer therapy. It is hypothesized that PARP1 inhibitors may prove highly effective therapies for cancers with BRCAness, due to the high sensitivity of the tumors to the inhibitor and the lack of deleterious effects on the remaining healthy cells with functioning BRCA HR pathway. This is in contrast to conventional chemotherapies, which are highly toxic to all cells and can induce DNA damage in healthy cells, leading to secondary cancer generation. Aging PARP activity (which is mainly due to PARP1) measured in the permeabilized mononuclear leukocyte blood cells of thirteen mammalian species (rat, guinea pig, rabbit, marmoset, sheep, pig, cattle, pigmy chimpanzee, horse, donkey, gorilla elephant and man) correlates with maximum lifespan of the species. Lymphoblastoid cell lines established from blood samples of humans who were centenarians (100 years old or older) have significantly higher PARP activity than cell lines from younger (20 to 70 years old) individuals. The Wrn protein is deficient in persons with Werner syndrome, a human premature aging disorder. PARP1 and Wrn proteins are part of a complex involved in the processing of DNA breaks. These findings indicate a linkage between longevity and PARP-mediated DNA repair capability. Furthermore, PARP can also act against production of reactive oxygen species, which may contribute to longevity by inhibiting oxidative damage to DNA and proteins. These observations suggest that PARP activity contributes to mammalian longevity, consistent with the DNA damage theory of aging. PARP1 appears to be resveratrol's primary functional target through its interaction with the tyrosyl tRNA synthetase (TyrRS). Tyrosyl tRNA synthetase translocates to the nucleus under stress conditions stimulating NAD+-dependent auto-poly-ADP-ribosylation of PARP1, thereby altering the functions of PARP1 from a chromatin architectural protein to a DNA damage responder and transcription regulator. The messenger RNA level and protein level of PARP1 is controlled, in part, by the expression level of the ETS1 transcription factor which interacts with multiple ETS1 binding sites in the promoter region of PARP1. The degree to which the ETS1 transcription factor can bind to its binding sites on the PARP1 promoter depends on the methylation status of the CpG islands in the ETS1 binding sites in the PARP1 promoter. If these CpG islands in ETS1