CEACAM5 and neoplasm: While several tumor biomarkers are routinely analyzed in biofluid samples, including alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), carcinoembryonic antigen 125 (CA125), carcinoembryonic antigen 153 (CA153), glycoconjugate antigen 199 (CA199), and prostate-specific antigen (PSA), they are all subject to somewhat limited sensitivity and specificity such that their utility for early-stage tumor detection is limited (5–7).