HOXA5 and neoplasm: A total of 219 CpG sites (185 hypermethylated and 34 hypomethylated) in 147 unique genes were significantly differentially methylated between tumor and tumor-adjacent gastric tissue (FDR = 0.001), with the top three CpG sites located in HOXA5, SFRP1 and CCNA1 [Additional file 2].