A third study reported a significant correlation between methylated ctDNA and CEA prior to surgery in 184 patients of all CRC stages (methylated SEPT9 r = 0.270, p = 0.001; methylated SHOX2 r = 0.313 p < 0.001) (Bergheim et al., 2018). Here, CEACAM5 is linked to colorectal carcinoma.