CEACAM5 and cancer: When applied for the detection of CEA, a commonly used clinical biomarker associated with various types of cancer, the assay displayed a linear dependence for 0–100 ng∙mL−1 range and an LOD of 5.66 ng∙mL−1 which is encouraging since in most individuals with cancer, CEA is often in the range from several to hundreds of ng∙mL−1.