ERBB2 and cancer: As such, we describe how these substrates enable the incorporation of antibodies against various cancer biomarkers [e.g., cancer antigen 15-3 (CA15-3), serum amyloid A1 (SAA1), epithelial cell adhesion molecule (EpCAM), or human epidermal growth factor receptor 2 (HER2)] for the detection of multiple malignancies.