Altered DNA methylation of CpG island shores in human colon cancer. Shown are an example of hypomethylation (Gene A, top) and hypermethylation (Gene B, bottom) in cancer revealed by a genome-scale analysis of the cancer methylome. Gene A is normally methylated at the shore and not at the island, and it acquires a hypomethylated pattern at the shore in colon cancer, resembling that of the normal liver. Aberrant expression at an alternate promoter, or for an untranslated RNA, is activated at the shore. Gene B is normally unmethylated at both shore and island, and it acquires a hypermethylated island at the shore, resembling the normal liver, and potentially at the island as well. Aberrant silencing ensues at the shore and potentially at the canonical promoter