OGG1 and adenoma: However, PARP-1 and OGG1 mRNAs retained the tendency to be lower in benign adenoma tissue than in colon tissue without histological changes (normal colon) of CRC patients (p = 0.00567 and p = 0.00149 respectively) and lower than in colon tumor tissue (p<0.00001 and p = 0.00156 respectively) - Fig. 1.