GRPR and breast cancer: Previous studies with [68Ga]Ga-labeled GRPR-antagonist SB3 (SB3, [DOTA-p-AMA-DGA-DPhe6,LeuNHEt13]BBN(6-13)) revealed the safety and feasibility of detecting GRPR-expressing pathological lesions of advanced BC and PC patients applying [68Ga]Ga-SB3 and PET/CT [29] with a more recent study in therapy-naïve PC patients revealing better results and reporting excellent correlation of imaging findings with GRPR-expression levels in the primary PC excised lesions [7].