A Study to Investigate Mechanisms of Resistance to Breast Cancer Therapies
This study will evaluate mechanisms of resistance to anti-breast cancer therapies in tumor and blood samples from participants with human epidermal growth factor receptor (HER2) positive, hormone receptor (HR) positive or triple negative breast cancer.
- EligibilityCriteria: General Inclusion Criteria:  Willingness to undergo a procedure to obtain tumor tissue (e.g. biopsy) and blood draw Diagnosis of HER2+, HR+ (for cohort R1) or triple negative breast cancer (for cohort T1) as per local assessment Availability of an archival tumor tissue (most recent pre-treatment tumor tissue is preferred) Unequivocally growing tumor lesion (progressive lesion) that is accessible for resection, excision or core needle biopsy Discontinuation of prior anti-cancer treatment outlined below should not be longer than 4 weeks from participation in this study  Inclusion criteria for participants in the cohorts studying acquired resistance  Participant had undergone regular monitoring for disease progression as per local practice (preferably every 3-6 months) while on most recent breast cancer therapy Accessible tumor lesion that newly appeared or a lesion that started to regrow while the participant was at least 6 months on therapy  Inclusion criteria for participants in the cohort studying primary resistance  Accessible tumor lesion that continued to increase in size or a newly appearing lesion (as confirmed by routine tumor assessment) while treated for at least 4 weeks but less than 6 months on therapy  Exclusion Criteria:  Any risks factors that increase the risk of complications associated with the procedure to obtain tumor tissue (e.g. bleeding disorders) Any serious medical condition or abnormality in clinical laboratory tests that precludes an individual's safe participation in and completion of the study Participant has started treatment with subsequent anti-cancer therapy Participants whose progressive tumor lesion that is targeted for biopsy/resection is in the bone Discontinuation of treatment was due to a reason other than disease progression - HealthyVolunteers: No - Gender: All - MinimumAge: 18 Years - StdAgeList: Adult, Older Adult