Carcinoembryonic antigen is the preferred biomarker for in vivo colorectal cancer targeting

TLDR

Colorectal cancer–specific biomarkers are used for imaging and drug delivery, yet biomarker selection is rarely evidence‑based. The study compared the sensitivities and specificities of CEA, TAG‑72, FRα, and EGFR by semi‑quantitative immunohistochemistry on matched mucosal and tumor tissues from 280 patients. CEA exhibited the greatest differential expression and the highest sensitivity (93.7%) and specificity (96.1%) for colorectal cancer detection, making it the preferred biomarker for in‑vivo targeting.

Abstract

Colorectal cancer-specific biomarkers have been used as molecular targets for fluorescent intra-operative imaging, targeted PET/MRI, and selective cytotoxic drug delivery yet the selection of biomarkers used is rarely evidence-based. We evaluated sensitivities and specificites of four of the most commonly used markers: carcinoembryonic antigen (CEA), tumour-associated glycoprotein-72 (TAG-72), folate receptor-α (FRα) and Epithelial growth factor receptor (EGFR).Marker expression was evaluated semi-quantitatively in matched mucosal and colorectal cancer tissues from 280 patients using immunohistochemistry (scores of 0-15). Matched positive and negative lymph nodes from 18 patients were also examined.Markers were more highly expressed in tumour tissue than in matched normal tissue in 98.8%, 79.0%, 37.1% and 32.8% of cases for CEA, TAG-72, FRα and EGFR, respectively. Carcinoembryonic antigen showed the greatest differential expression, with tumours scoring a mean of 10.8 points higher than normal tissues (95% CI 10.31-11.21, P<0.001). Similarly, CEA showed the greatest differential expression between positive and negative lymph nodes. Receiver operating characteristic analyses showed CEA to have the best sensitivity (93.7%) and specificity (96.1%) for colorectal cancer detection.Carcinoembryonic antigen has the greatest potential to allow highly specific tumour imaging and drug delivery; future translational research should aim to exploit this.