Evaluating Minimal Residual Disease (MRD) Through Longitudinal Circulating Tumor DNA (ctDNA) Profiling in Breast Malignancies

Inclusion Criteria:

All Cohorts:

1. Willing and able to participate in the research and provide biospecimens

2. Willing and able to provide informed consent

3. Must be diagnosed with breast cancer

Cohort 1: Neoadjuvant Treatment Cohort 1A: Newly Diagnosed, High Risk HR+,HER2-

1. A known or suspected HR+, HER2- breast cancer treated with curative intent (Stage IIto III disease)

2. Patients are considered at high risk of recurrence, defined as 4 or more positiveaxillary lymph nodes (ALNs), or between 1-3 positive ALNs and either grade 3 diseaseor tumor size of 5 cm or larger.

Cohort 1B: HER2+ 1. A known or suspected HER2+ breast cancer treated with curative intent (Stage II to III disease). Inclusive of HR+ or HR- patients.

Cohort 1C: Triple Negative Breast Cancer

1. A known or suspected triple negative breast cancer treated with curative intent (Stage I to III disease).

Cohort 2: Adjuvant Therapy / Surveillance Cohort 2A: Newly Diagnosed HR+,HER2-

1. A known or suspected HR+, HER2- breast cancer treated with curative intent (Stage IIto III disease)

2. Patients are considered at high risk of recurrence, defined as 4 or more positiveaxillary lymph nodes (ALNs), or between 1-3 positive ALNs and either grade 3 diseaseor tumor size of 5 cm or larger.

3. Have undergone curative intent surgery with no clinical evidence of disease.

Cohort 2B: HER2+

1. A known or suspected HER2+ breast cancer treated with curative intent (Stage II toIII disease)

2. Have undergone curative intent surgery with no clinical evidence of disease.

Cohort 2C: Triple Negative Breast Cancer

1. A known or suspected triple negative breast cancer treated with curative intent (Stage I to III disease)

2. Have undergone curative intent surgery with no clinical evidence of disease.

Cohort 3: 5-Years Post-Diagnosis Surveillance (NED)

1. A known HR+, HER2- breast cancer treated with curative intent (Stage II to IIIdisease).

2. No Evidence of Disease (NED) ≥ 5 years from initial diagnosis.

3. Patients are considered at high risk of recurrence, defined as 4 or more positiveaxillary lymph nodes (ALNs), or between 1-3 positive ALNs and either grade 3 diseaseor tumor size of 5 cm or larger.

Exclusion Criteria:

1. Not willing or able to adhere with the study procedures

2. Active secondary malignancy

3. Diagnosis of a malignancy within 3 years of breast cancer diagnosis Note: Ductalcarcinoma in situ (DCIS, ipsilateral or contralateral) within 3 years is notexcluded.