PET/CT for Trop2 ADC Response Evaluation Cancers

Inclusion Criteria: * adult patients (aged 18 years or order) * histologically or cytologically confirmed metastatic breast cancer previously treated with systemic therapy, supported by imaging (e.g., MRI, CT), tumor markers, or pathology reports * presence of at least one measurable lesion according to the Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1 * willingness to undergo serial 68Ga-MY6349 PET/CT scans before and during Trop2-ADC therapy * Eastern Cooperative Oncology Group (ECOG) performance status of 0-1 * Ability to provide written informed consent and, where applicable, assent in accordance with the requirements of the Clinical Research Ethics Committee Exclusion Criteria: * Evidence of significantly impaired hepatic or renal function * Estimated life expectancy of less than 3 months