EGFR as a biomarker in colorectal Cancer: An electrochemical biosensing approach

Traditional epidermal growth factor receptor (EGFR) evaluation in colorectal cancer (CRC) is conducted using conventional immunohistochemistry (IHC), which has shown interlaboratory concordance variability (50-68%) and has not been effective in predicting therapeutic response, thereby requiring advanced diagnostic methods to enhance patient outcomes. This extensive literature review synthesizes the available evidence in the field of electrochemical detection of EGFR protein, circulating tumor deoxyribonucleic acid (ctDNA) mutations, and integrated multi-biomarker assays as analytically superior alternatives to traditional methods of analysis. Electrochemical platforms can achieve sensitivity at picomolar-to-attomolar concentrations and have response times of minutes to hours, which is much faster than the 3-5 days for immunohistochemistry turnaround, and can be used to facilitate rapid clinical decisions. Multiplexed biomarker integration (electrochemical EGFR) quantification with concomitant ctDNA detection, extracellular vesicle (EV) proteomic characterization, and serum biomarker detection (carcinoembryonic antigen (CEA), cancer antigen 125 (CA125), micro ribonucleic acid (miRNA) signatures) provides comprehensive tumor phenotyping, enabling patient stratification for cetuximab or panitumumab monoclonal antibody therapy with a reported 76.9% diagnostic accuracy in predicting therapeutic response. Systemic clinical implementation requires multicenter prospective comparative studies, regulatory approval (Food and Drug Administration (FDA) 510(k)/de novo; Conformité Européenne (CE) marking), and point-of-care deployment in community oncology facilities and healthcare environments with constrained resources. Electrochemical EGFR biomarking is a clinically practicable analytical platform for advancing precision oncology using accessible, quantitatively precise multiplex biomarkers that can be used across a wide range of healthcare systems.