Associations among dietary seaweed intake,c-MYCrs6983267 polymorphism, and risk of colorectal cancer in a Korean population: a case-control study

Purpose The effects of seaweed compounds have been studied in relation to colorectal cancer (CRC) based on their ability to modulate carcinogen metabolism in vivo and in vitro. However, no epidemiological studies on the interaction between edible seaweed and genetic variants relevant to CRC have been reported. This study examined the associations among dietary seaweed intake (gim, miyeok, and dashima), single-nucleotide polymorphisms (SNPs; rs6983267, rs7014346, and rs719725), and CRC risk in a Korean population. Methods The participants comprised 923 CRC patients and 1846 controls who visited the National Cancer Center Korea. We used a Semiquantitative Food Frequency Questionnaire and genotyped SNPs using genomic DNA samples. Results The intake of total seaweed, miyeok, and dashima showed a significant inverse association with CRC risk after adjusting for potential confounding factors (total seaweed odds ratio (OR) [95% CI] = 0.65 [0.50-0.85],Pfor trend < 0.001; miyeok = 0.82 [0.62-1.09],Pfor trend < 0.05; dashima = 0.58 [0.44-0.76],Pfor trend < 0.001, highest vs. lowest tertile). We confirmed that the homozygous T/T allele of rs6983267c-MYCindicated an interaction between dietary seaweed intake and both overall CRC and rectal cancer (CRC OR [95% CI] = 0.52 [0.34-0.81],Pfor interaction = 0.015; rectal cancer = 0.45 [0.25-0.79],Pfor interaction = 0.007, T/T carriers with high total seaweed intake vs. T/T carriers with low total seaweed intake). Conclusions This study provides evidence of the effect of dietary seaweed intake on CRC risk with respect toc-MYCgene variants.