COL4A2 and colorectal carcinoma: Among them, 12 genes were not hypermethylated in any of the normal colon samples, but were frequently methylated (>75%) in CRC cases: COL4A2 (147/149), TSPYL5 (141/149), TMEFF2 (141/149), RASSF2 (134/149), SPG20 (130/149), EDIL3 (130/149), CIDEB (128/149), ADAMTS1 (128/149), EFHD1 (127/149), STOX2 (126/149), PPP1R3C (118/149), and UCHL1 (115/149) (Fig.1).