The mRNA level of ID1 was up-regulated in primary CRC tissues compared with normal controls, with fold-changes of 2.727 in the colon adenoma [19], 3.129 in the rectal adenoma [19] and 2.021 in the colorectal adenocarcinoma [20] (Figure 1B–D). Here, ID1 is linked to colorectal adenocarcinoma.