SEPTIN9 and colorectal carcinoma: Since earlier studies analyzed DNA methylation changes only in a single SEPT9 CpG island, and only in heterogeneous CRC tissue specimens, this study aims at determining whether the aberrant methylation changes are unique to only this CpG island or whether hypermethylation affects multiple CpG dense regions associated with this gene and how SEPT9 methylation is affected in homogeneous populations of epithelial and stromal cells.