The validity of this list is supported by (i) the presence of many genes which were previously found to be downregulated in colorectal cancer (e.g. CHGA, FCGBP, GSN, LPP, MYH11, PLCG2, SST, NBL1) [42], [43], (ii) the presence of several known tumor suppressor genes (e.g. CDKN2B, MTUS1, RASSF6, PDCD4, KLF5, CDS1), and (iii) by the results of principal component analyses performed on previously published data sets. Here, PDCD4 is linked to colorectal cancer.