The performance of Ioncopy was evaluated by (i) comparing the detected HER2 CNAs with the HER2 status determined by the gold standard of immunohistochemistry (IHC) and ISH [12], (ii) comparing the CNs detected by different amplicons interrogating the same gene, (iii) analyzing the overall CNA landscape of all 48 genes covered by the panel and (iv) correlating the Ioncopy CNA calls with the tumor RNA expression of the corresponding gene. The gene discussed is ERBB2; the disease is neoplasm.