ERBB2 and breast cancer: Integer ERBB2 copy number inferred from MSK-IMPACT data revealed that ERBB2 amplified esophagogastric cancers had the highest median ERBB2 copy number (26, inter-quartile range IQR:10-42.75), followed by colorectal and breast cancers (22, IQR: 9-36 and 21, IQR:12-36, respectively), with median ERBB2 copy number lower in urothelial cancers (17.5, IQR:8.25-29.25) (Fig. 1C).