ERBB2 and neoplasm: If the result of the recount remains the same (HER2/CEP17 ratio <2.0; average HER2 copy number ≥4.0 and <6.0), then the tumor is considered HER2 negative.9 While the new guideline represents a much-needed practical approach to these difficult to categorize tumors, more information about the biology of these tumors, and in particular, more data about outcome after trastuzumab treatment in this group of tumors, would help support treatment decisions.