The PET tracer-based GRPR radioantagonist 68Ga-DOTA-p-aminomethyl aniline-diglycolic acid-D-Phe-Gln-Trp-Ala-Val-Gly-His-Leu-NHEt (68Ga-SB3) has shown excellent tumor localizing efficacy and pharmacokinetics in animals and patients with prostate and breast cancers (Maina et al., 2016; Lymperis et al., 2018). Here, GRPR is linked to breast carcinoma.