In recent years, intensive efforts have been undertaken to identify blood-based markers that may provide a promising alternative or supplement to fecal testing for non-invasive CRC screening. One method under development is to identify aberrantly methylated genes in cancer tissue through a blood test. Prior studies have explored those specific colorectal cancer genes that show the highest differences in methylation between the cancer and background genetic expression. Of these, methylation of the Septin 9 gene through a qPCR assay is relatively well studied.