The median HER2:EFTUD2 copy number ratio in HER2 amplified cancers (7.0, range 2.04–26.5) was significantly higher than in HER2 non-amplified (1.07, range 0.53–2.00, p<0.0001 Mann Whitney U test), with the receiver operator curve area under the curve of 1.0 (95% CI undefinable). This evidence concerns the gene ERBB2 and cancer.