Simplified Chromatography-based Purification approach with utilizing Tangential Flow Filtration for Colorectal Cancer...

Carcinoembryonic antigen (CEA) is a clinically important biomarker for cancer diagnosis and prognosis, particularly in colorectal cancer. This investigation introduces a simplified approach for the purification of native CEA antigen from the ascitic fluid of patients with colorectal cancer. Moreover, the technique allows the characterization of CEA though ensuring its structural and functional integrity is preserved. The CEA purification was achieved using perchloric acid precipitation, tangential flow filtration and sequential chromatography. The isolated CEA showed a relative molecular mass of ∼200 kDa and was analyzed using SDS-PAGE, size-exclusion FPLC and immunoblotting, confirming high purity comparable to reference form of native CEA protein. Peptide mass fingerprinting of trypsin-digested and deglycosylated CEA antigen identified it as CEACAM5_HUMAN (Uniprot ID: P06731). The proposed method demonstrates the adaptability for larger volume and practical approach for production of native form of CEA protein, also potential utility for future diagnostic applications, clinical research and bioanalytical studies.