When CRC was compared to normal colonic mucosa, the subgroup analyses based on ethnicity showed that SFRP1 methylation had a significant heterogeneity in the Caucasians subgroup (I2 = 84.4%) but not in the Asian subgroup (I2 = 35.9%), which suggests that the heterogeneity was from the Caucasian population. The gene discussed is SFRP1; the disease is colorectal carcinoma.