ERBB2 gene expression. a. ERBB2 (HER2) expression for the three probes on the 1.5K panel. b. ERBB2 (HER2) expression for the three probes on the 24K panel. From left to right the three probes are ordered from the 5-prime to 3-prime end of ERBB2. The ERBB2 probe positions for the 1.5K panel are: 607 for GI.4758297.S.1789-5prime; 1192 for GI.4758297.S.1787-middle; and 4106 for GI.4758297.S.1786-3prime. The ERBB2 probe positions for the 24K panel are: 47 for ILMN_1717902-5prime; 370 for ILMN1728761-middle; and 4390 for ILMN_2352131-3prime. Internal to each probe the samples are sorted by HER2 IHC 0-3+ values. Open circles represent tumors with HerceptTest IHC scores of 0-1+ and closed triangles represent tumors with HerceptTest IHC scores of 2-3+.