In this study, for the first time, we report the use of novel Hb-AgNCs@MOF-G nanocomposite for the immobilization of anti-HER2 on a glassy carbon electrode (GCE) and its bioapplication for fabrication of a label free electrochemical immonusensor for the detection of HER2-positive breast cancer cells based on both Square Wave Voltammetry “signal off” and impedimetric “signal on” methods (Fig. 1). This evidence concerns the gene ERBB2 and breast cancer.