EGFR and breast cancer: Panitumumab-[197Hg]Hg-AuNPs exhibited high affinity binding to EGFR on U251-Luc cells (Fig. 1) with a KD = 1.8 × 10–9 mol/L comparable to [177Lu]Lu-DOTA-panitumumab (1.0 × 10–9 mol/L) binding to EGFR-positive MDA-MB-468 human breast cancer cells (Aghevlian et al. 2018).