Confirmation of the thesis of common effect of polymorphisms of different genes to modulate the risk of cancer is also observed by us as protective effect in form of reducing the risk of CRC for genotype pairs (51Gln/His APEX-148Glu/Glu APEX and 51Gln/His APEX-23Gly/Gly XPA) where one of the polymorphisms previously increased the risk, so we can see a reversal of the trend. Here, APEX1 is linked to colorectal carcinoma.