An insertion/deletion polymorphism within the promoter of EGLN2 is associated with susceptibility to colorectal cancer.

OBJECTIVE: To investigate the association between susceptibility to colorectal cancer (CRC) and a 4-bp insertion/deletion polymorphism (rs10680577) in the proximal promoter of the EGLN2 gene.

METHOD: The first step in genotyping EGLN2 was PCR, then the PCR products were separated using 7% nondenaturing polyacrylamide gel electrophoresis and visualized by silver staining according to the final product band location and quantity to determine the genotype of the sample. The final count was done by two different pathologists.

RESULT: In the codominant model, compared with the ins/ins genotype, subjects with the heterozygous ins/del or homozygous del/del genotype had a significantly increased risk of CRC (adjusted OR = 1.45, p<0.0001 and OR = 2.44, p = 0.0001, respectively). Each additional copy of the 4-bp deletion allele conferred a significantly increased risk of CRC (OR = 1.47, 95% CI 1.28-1.66, p<0.0001). In the stratification analysis, we further proved that the association was more prominent in TNM stage III and IV cancer compared with stage I and II (adjusted OR = 1.43, 95% CI 1.07-1.93, p for heterogeneity = 0.02).

CONCLUSIONS: Our study provided initial evidence that the insertion/deletion polymorphism rs10680577 may play a functional role in the development of CRC in the Chinese population.