EN1 and colon carcinoma: The methylation status of three additional CpG islands (CpG104, CpG 41 and CpG 173) flanking the EN1 CpG island (CpG128) (see Supplementary Figure 3B) was determined in a subset of 23 colon carcinomas and their matched normal mucosa from the series of 108 cases by PCR MC analysis.