The occurrence of polymorphic variants in 51Gln/His, 64Ile/Val, and 148Asp/Glu of APEX gene; 23Gly/Ala of XPA gene; and 689Ser/Arg of ERCC4 gene was studied with the TaqMan technique.
We did not find any significant influence of 64Ile/Val polymorphism of APEX gene (Table 5) and 689Ser/Arg polymorphism of ERCC4 gene (Table 6) on modulation of CRC risk.
Moreover, increased risk of colorectal cancer was revealed for pairs Gln/His-Arg/Arg (51Gln/His APEX-689Ser/Arg ERCC4), Val/Val-Asp/Glu (64Ile/Val APEX-148Asp/Glu APEX), Val/Val-Gly/Ala (64Ile/Val APEX-23Gly/Ala XPA), and Asp/Glu-Gly/Ala (148Asp/Glu APEX-23Gly/Ala XPA); while at the same time, risk was decreased for pairs Ile/Val-Asp/Asp (64Ile/Val APEX-148Asp/Glu APEX), Ile/Val-Gly/Gly, and Ile/Val-Ala/Ala (64Ile/Val APEX-23Gly/Ala XPA) as well as Asp/Asp-Gly/Ala and Asp/Glu-Gly/Gly (148Asp/Glu APEX23Gly/Ala XPA).
The first thing worth noting is the increased risk of CRC in the case of co-occurrence of genotype 51Gln/His of APEX gene with 64Val/Val of APEX gene when compared to risk associated only with 51Gln/His (OR 2.266 (1.1204.585); p = 0.022 versus 1.706 (1.174-2.480); p = 0.005) and similar increased risk of CRC in the case of co-occurrence of genotype 51Gln/His of APEX gene with 689Arg/Arg ERCC4 (OR 2.464 (1.247-4.870); p = 0.009 versus 1.706 (1.174-2.480); p = 0.005).
Genotypes 51Gln/His and 148Asp/Glu of APEX gene and 23Gly/Ala of XPA gene may increase the risk of CRC, while polymorphisms of 64Ile/Val of APEX gene and 689Ser/Arg of ERCC4 gene have no effect on modulating the risk.
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