Abstract: Background: The objective of our investigation is to study the relationship between the rs4939827 SNP in the
SMAD7 gene, Mediterranean diet pattern and the risk of colorectal cancer.
Methods: We examined 1087 cases of colorectal cancer and 2409 population controls with available DNA samples
from the MCC-Spain study, 2008?2012. Descriptive statistical analyses, and multivariate logistic mixed models were
performed. The potential synergistic effect of rs4939827 and the Mediterranean diet pattern was evaluated with
logistic regression in different strata of of adherence to the Mediterranean diet and the genotype.
Results: High adherence to Mediterrenean diet was statistically significantly associated with colorectal cancer risk. A
decreased risk for CRC cancer was observed for the CC compared to the TT genotype (OR = 0.65 and 95% CI = 0.51?0.
81) of the rs4939827 SNP Also, we could show an association between the Mediterranean diet pattern (protective
factor) and rs4939827. Although the decreased risk for the CC genotype was slightly more pronounced in subjects with
high adherence to Mediterrenean diet, there was no statistically significant synergistic effect between genotype CC
and adherence to the Mediterranean dietary pattern factors.
Conclusion: The SMAD7 gene and specifically the allele C could be protective for colorectal cancer. An independent
protective association was also observed between high adherence Mediterranean diet pattern and CRC risk. Findings
form this study indicate that high adherence to Mediterranean diet pattern has a protective role for CRC cancer
probably involving the Tumor Growth Factor- ? pathway in this cancer.