ERBB2 and breast cancer: Utilizing gap-enhanced Raman nanotags combined with machine learning algorithms, Rodriguez-Nieves et al. (11) effectively detected and classified surface proteins associated with three distinct molecular subtypes of breast cancer, enabling precise molecular subtyping Khosroshahi et al. (35) developed a label-free SERS immunosensor based on plasmon-activated nanostructured films capable of detecting HER-2 overexpression (2+, 3+, and positive) in patient serum.