PARP1 and colorectal carcinoma: High positive correlation was found between mRNA level of PARP-1 and OGG1 (Fig. 2) in leukocytes of healthy volunteers (r = 0.7829), AD patients (r = 0.8139), and CRC patients (r = 0.6772), as well as in all colon tissues of CRC patients (Fig. 2).