In CRC patients who are below of 30th percentile of vitamin D, SFRP2 methylation did not correlate with methylation of colorectal carcinogenesis genes, although SFRP2 methylation in tumor area was positively correlated with SFRP2 methylation in tumor-free area (p < 0.05) (Fig. 3a). Here, SFRP2 is linked to colorectal carcinoma.