ERBB2 and neoplasm: The prevalence of ERBB2 activating alteration types varied significantly across these cancer types (AMP: 3.7%–15.5%, MUT: 1.9%–8.8%, and RE: <0.01–0.09%), as did the prevalence of ERBB3 activating alterations (AMP: <0.1%–2.2% and MUT: 1.1%–5.2%; Fig. 1D), and frequencies also varied by histology within a given tumor type (Supplementary Tables S1 and S2).