ERBB2 and breast carcinoma: Bladder and CUP had higher CNV amplification and/or IHC overexpression than previous publications.38 Discrepancies in expression patterns are likely because of lack of HER2 standardization among non–breast cancer patients, tumor heterogeneity, various HER2 positivity cutoff, and variability between different laboratories.39 Furthermore, wide variability of HER2 amplification and overexpression rates is reported in the literature, making comparisons difficult.19