GeneSearch™ Breast Lymph Node (BLN) Assay Post Approval Study

Inclusion Criteria: * Pre-operatively established diagnosis of invasive carcinoma of the breast * Scheduled for axillary sentinel lymph node dissection as per standard of care at the clinical site for newly diagnosed breast cancer patients * Patients for whom the GeneSearch™ BLN Assay will be used intra-operatively to make a decision for an axillary lymph node dissection * 18 years of age or older * Female or male * Willing and able to give informed consent to participate in the study Exclusion Criteria: * Previous diagnosis of lymphoma * Subjects participating in other research studies that would interfere with their full participation in this study * Patients and/or conditions with 'interfering substances' as listed in the IFU. * Patients who have had any pre-operative treatment for breast cancer including neoadjuvant and/or hormonal intervention such as aromatase inhibitors or tamoxifen