HER2 status should be reported as an equivocal result if an HER2/CEP17 ratio < 2.0 with an average HER2 copy number ≥ 4.0 and < 6.0 per tumor cell is detected by dual-probe FISH assay, according to the 2013 ASCO/CAP HER2 testing guidelines. This evidence concerns the gene ERBB2 and neoplasm.