ERBB2 and cancer: The median ERBB2 amplification ratio (amp ratio, i.e., ratio of the modeled gene copy number to sample ploidy) ranged from 1.78 to 12.52 across tumor types (Q1 = 1.55–5.72, Q3 = 2.23–28.31), with salivary gland (median 12.52, IQR = 5.72–23.12), GEC (median 7.00, IQR = 2.83–27.63), breast (median 6.99, IQR = 2.45–15.46), colorectal (median 6.37, IQR = 2.23–28.31), and non-melanoma skin (median 6.14, IQR = 2.86–16.81) cancers exhibiting the highest median amp ratio across tumor types (Supplementary Fig. S1A).