This study will assess a dose of ABY-025 followed by a tracer dose of \[68Ga\]Ga-ABY-025 in subjects with HER2+ solid cancers, or HER2+ or low breast cancer undergoing or planning to undergo treatment with standard-of-care HER2-targeted therapy for an FDA-approved indication. The study drug will be administered and \[68Ga\]Ga-ABY-025 PET/CT scan will be obtained the same day after injection of study drug. Patients will have a follow visit 2-7 days post injection of the study drug. Additionally, subjects will undergo standard of care evaluation of their advanced disease per the discretion of their treating physician.
