Overexpression in tumor cells and the correlation between the elevated serum levels of soluble CEA (sCEA) shedding from tumor cells with disease progression made CEA as one of the most important biomarkers in cancers, such as colorectal cancer (CRC).67, 68, 69 On the other hand, sCEA may interfere with immunotherapy approaches targeting membrane-bound CEA.67, 68, 69 To that end, Lutterbuese et al.67 This evidence concerns the gene CEACAM5 and colorectal carcinoma.