Methylation analysis of CD133 gene in primary CRC tissues versus normal colon tissues. (A) normal colon tissues (B) primary CRC tissues. M=methylation signal; U=unmethylated signal. IVD= in vitro methylated DNA. ddH2O=water control adding no DNA. Numbers represent normal colon (5, 21–23, 25–38, 40) and primary CRC samples (71, 73–83, 85–86, 88–89).