ERBB2 and breast carcinoma: developed SERS nanotags based on Ag‐encapsulated Au (Ag–Au) hollow nanospheres with three Raman reporters (MGITC, RBITC, DTDC) positioned in nanogaps to enhance the electromagnetic field.[248] Through conjugation with specific antibodies, these nanotags enabled simultaneous and quantitative detection of multiple breast cancer biomarkers (EpCAM, ErbB2, and CD44) via SERS mapping techniques.