Elevated CEA levels have beenobserved in the blood samples of CRC patients, with overexpressiondetected in 90–95% of CRC cases.45−47 Tiernan et al. revealedthat CEA displayed the most significant differential expression betweentumor and normal tissues.48 Moreover, inthis study, CEA demonstrated significant differential expression betweenpositive and negative lymph nodes, outperforming other CRC markerssuch as TAG-22, FRα, and EGFR.48 The gene discussed is CEACAM5; the disease is colorectal carcinoma.