ERBB2 and breast cancer: The analysis of the PC formed around AuNPs (10.02 ± 0.91 nm) after their interaction with serum samples of 42 BC patients allowed the identification of 194 potential protein biomarkers, of which 72 have been found in patients with the LA subtype, 82 in the LB−, 59 in the LB+, 36 in the HER2+ and 59 in the TNBC subtype.