PPY and rectal cancer: In the subgroup analyses based on tumor site, FGF-21 (OR: 1.23, 95% CI 1.03–1.47) and 5’NT (OR: 0.86, 95% CI 0.79–0.99), were associated with colon but not rectal cancer, whereas PPY (OR: 1.47, 95% CI 1.12–1.92) was associated with rectal but not colon cancer.