Fig. 4

Visceral adipose tissue methylation analysis: correlation between SFRP2 promoter methylation status and methylation of genes related to adipogenesis and inflammation in visceral adipose tissue from CRC patients, according to the 30th percentile of vitamin D. Correlation between SFRP2 promoter methylation analyses in PBMCs (N = 52), tumor area (N = 60), tumor-free area (N = 55), and VAT (N = 50) from CRC patients and C/EBPα, PPARγ, PGC1α, NFκB, TNFα, VDR, and ZNF543 promoter methylation in tumor area, according to the a < 30th percentile and b > 30th percentile of vitamin D. Pearson’s correlation was performed to determine correlation between methylated genes. Data are expressed as correlation coefficient. Colored square indicates significant difference between methylated genes according to Pearson’s analysis (p < 0.05). Abbreviations: CRC, Colorectal cancer; SFRP2, Secreted frizzled-related protein type 2; PBMCs, peripheral blood mononuclear cells; VAT, Visceral adipose tissue; C/EBPα, CAATT/Enhancer Binding Protein type α; PPARγ, Peroxisome proliferator activator receptor type γ; PGC1α, PPARγ coactivator type 1α; NFκB, nuclear factor κ B; TNFα, Tumor necrosis factor type α; VDR, Vitamin D receptor; ZNF543, Zinc finger protein type 543