Similarly, another crucial breast cancer biomarker, human epidermal growth factor receptor 2 (HER-2), was detected in serum samples by developing a low-cost and effective immunosensor based on AuNS modified on a laser-scribed graphene (LSG) electrode, demonstrating an LoD of 0.008 ng/mL and good reproducibility. This evidence concerns the gene ERBB2 and breast cancer.