PARP1 and cancer: In addition, despite a general decline in PARP activity with age (Grube and Bürkle, 1992; Chevanne et al, 2007) that may correspond to the increase in cancer incidence with age (http://info.cancerresearchuk.org/cancerstats/mortality/age/), lymphocytes from people who live to a very old age (>100 years) without developing cancer have higher PARP activity (Muiras et al, 1998).