The usual approach to care for hormone receptor positive, HER2 positive breast cancer is chemotherapy and HER2 targeted therapy followed by endocrine therapy and surgery.

The purpose of this Research Study is to see if taking endocrine therapy with the chemotherapy and HER2 directed therapy increases patients response to therapy at the time of surgery

Inclusion Criteria:

1. Adults over 18 years of age with newly diagnosed, previously untreated, HR+, HER2+ breast cancer (positive per local guidelines)

   1. Endocrine therapy for the current breast cancer may be started within 28 days prior to trial enrollment and must be initiated prior to C2 of chemotherapy/HER2 directed therapy
   2. Choice of endocrine therapy will be determined by the treating and/or enrolling physician

2. Anatomic Stage IIA - IIIC breast cancer planning a minimum of 4 cycles of TCHP

3. Patients must be Luminal A, Luminal B or HER2 enriched subtype on MammaPrint/BluePrint performed on initial biopsy

Exclusion Criteria:

1. Children under 18 years of age, pregnant women, prisoners, and decisionally impaired adults.
2. Patients with non-breast cancer within prior 2 years
3. Patients with breast cancer within prior 5 years
4. Patients with recurrent breast cancer
5. Patients with stage IV breast cancer