Colorectal cancer-susceptibility single-nucleotide polymorphisms in Korean population

Background and aim: Considering the significant racial and ethnic diversity in genetic variation, it is unclear whether the genome-wide association studies-identified colorectal cancer (CRC)-susceptibility single-nucleotide polymorphisms (SNPs) discovered in European populations are also relevant to the Korean population. However, studies on CRC-susceptibility SNPs in Koreans are limited.

Methods: To investigate the racial and ethnic diversity of CRC-susceptibility genetic variants, we genotyped for the established European CRC-susceptibility SNPs in 198 CRC cases and 329 controls in Korea. To identify novel genetic variants using genome-wide screening in Korea, Illumina HumanHap 370K/610K BeadChips were performed on 105 CRC patients, and candidate CRC-susceptibility SNPs were selected. Subsequently, genotyping for replication was done in 189 CRC cases and 190 controls.

Results: Among the European CRC-susceptibility SNPs, rs4939827 in SMAD7 was associated with a significant decreased risk of Korean CRC (age-/gender-adjusted odds ratio [95% confidence interval]: additive model, 0.67 [95% CI, 0.47-0.95]; dominant model, 0.59 [95% CI, 0.39-0.91]). rs4779584 and rs10795668 were associated with CRC risk in females and males, respectively. Among candidate CRC-susceptibility SNPs selected from genome-wide screening, novel SNP, rs17051076, was found to be associated with a significantly increased risk of microsatellite instability-high CRC (age-/gender-adjusted odds ratio [95% confidence interval]: additive model, 4.25 [95% CI, 1.51-11.98]; dominant model, 3.52 [95% CI, 1.13-10.94]) in the replication study.

Conclusions: rs4939827, rs4779584, and rs10795668 may contribute to the risk of CRC in the Korean population as well as in European populations. Novel rs17051076 could be associated with microsatellite instability-high CRC in Koreans. These associations support the ethnic diversity of CRC-susceptibility SNPs and should be taken into account in large-scale studies.