Fig. 4

CpG islands methylation of the HPSE2 promoter. a Heat map of 49 methylated CpG islands located in the promoter region of HPSE2 from TCGA database; b Pearson correlation of methylation sites and HPSE2 expression with cor < − 0.3 were selected; c Differentially methylated CpG islands between normal and tumor tissues from TCGA database; d Differentially methylated CpG islands of the HPSE2 promoter among adenocarcinoma, adenoma, and normal tissues from the GSE68484 dataset. ***P < 0.001