Finally, when deepened in the study of the seven CpG islands of SFRP2 promoter of tumor colon area, the methylation of CpG sites 1, 2, 3, and 4 was significantly decreased in the > 30th group, when compared to the < 30th group (p < 0.05) (Fig. 1c). Here, SFRP2 is linked to neoplasm.