The primary objective of this clinical study is to gather data to estimate the positive predictive concordance (PPC) between the GeneSearch™ BLN Assay and histology as routinely practiced, i.e., routine H&E histology of sentinel lymph node(s) (SLN) and, when available, routine histology of non-sentinel axillary lymph nodes (ALN). This study will provide information on the assay that will augment the performance data gained in pre-market validation studies. In addition, with the assay being used for ALND decision-making, the metastatic status of the non-sentinel axillary nodes can be taken into account in the performance measures, i.e., if the patient's sentinel or non-sentinel nodes are histologically positive, the patient will be considered positive for the primary comparison to the assay results.