Breast cancer biomarkers are usually performed on core needle biopsy (CNB) specimens and are not routinely repeated on surgical specimens (SS). However, preliminary data suggests that testing these biomarkers, on SS when compared to CNB samples can lead to different results. Our hypothesis is that The aim of this study is to identify a group of women with invasive breast cancer who may benefit from additional HER2 testing on their SS to ensure that areas of HER2 amplification are not missed. Another aim is to determine whether further HER2 testing on the SS in select patients would lead to changes in breast cancer treatment options.

Inclusion Criteria:

1. Women > age 18 with capacity to consent
2. Invasive breast cancer identified on CNB at AAMC within 45 days of study consent
3. IHC biomarkers performed on original CNB (including HER2)
4. Tumors with greater than 2cm of invasive disease (measured radiographically prior to resection or microscopically after resection), or
5. Multifocal or multicentric tumors

Exclusion Criteria:

1. Men
2. Women with HER2 positive tumors detected on CNB specimens
3. Women receiving neoadjuvant chemotherapy
4. Women whose CNB or surgical resection was performed at a hospital other than AAMC. If the CNB prior to resection was repeated at AAMC and new tumor biomarkers were performed, then the patient is eligible for enrollment
5. Women whose IHC marker results were inconclusive on CNB or not performed -

Breast Cancer pre-surgical patients