Fig. 4: Copy number estimation of ERBB2 based on next generation sequencing (NGS) calculated tumor purity.

A Absolute ERBB2 copy number by fluorescence in situ hybridization (FISH) versus NGS (linear regression R2 = 0.88). B Comparison of ERBB2/CEP17 copy number ratio by FISH versus ERBB2/NF2 copy number ratio by NGS (linear regression R2 = 0.76). C NGS data plots of log2(read ratio) for chromosome 17 from three representative invasive breast carcinoma cases; each dot represents read ratio data point from target genes included in the NGS panel; “C” denotes location of centromere and shaded boxes labeled NF1 and ERBB2 denote the read ratios corresponding to these target genes. Top: focal ERBB2 amplification, positive by FISH and NGS. Middle: ERBB2 gain as part of chromosome 17q gain, negative by FISH and NGS. Bottom: ERBB2 gain as part of complex chromosome 17q copy number changes, positive by FISH and NGS.