We examined assay characteristics and the performance of the DASL 502-gene Cancer Panelv1 (1.5K) and 24,526-gene panel (24K) platforms at differentiating nine human epidermal growth factor receptor 2- positive (HER2+) and 11 HER2-negative (HER2-) paraffin-embedded breast tumors. This evidence concerns the gene ERBB2 and breast neoplasm.