Diet-drive Gut Microbiome and Outcome in Patients With Early-stage Triple-negative Breast Cancer Undergoing Neoadjuvant Chemotherapy and Immunotherapy.

Inclusion Criteria: * Willing and able to provide written informed consent prior to study entry * Female ≥ 18 years of age * Histologically confirmed operable primary breast cancer with a tumor size of ≥1 cm * Triple-negative disease: * defined as tumours with \<10% of tumours cells positive for ER and PR1 on IHC staining or an IHC score (Allred) \< 3 * HER2-negative tumours defined as 0, 1+ or 2+ intensity on IHC and no evidence of amplification of the HER2 gene on ISH. defined as tumours with * Patient planned to undergo neoadjuvant chemotherapy (as per institutional standard) with/without immunotherapy * Representative formalin-fixed paraffin embedded (FFPE) breast tumours samples with an associated pathology report that are determined to be available and sufficient for central testing OR tumours accessible for biopsy. * Ability to comply with the protocol, including but not limited to, completion of the patient-reported outcomes questionnaires Exclusion Criteria: Patients meeting any of the following exclusion criteria are not be enrolled in the study. * Previous systemic or local treatment for the new primary breast cancer currently under investigation (including surgery, radiotherapy, cytotoxic and endocrine treatments) * Received therapeutic oral or intravenous antibiotics within 14 days prior to randomization * Known distant metastases