Many reports showed that increased sialylation of proteins is associated with strong invasiveness and poor prognosis of cancer patients.50, 51 Moreover, several researches demonstrated that antibodies targeting sialic acid epitope had preferential specificity than that against core protein for biomarker detection.52 Currently, many antibodies targeting glycosyl epitope, such as CA19‐9, CA72‐4, and CEA, have been widely applied for clinical detection. The gene discussed is CEACAM5; the disease is cancer.