ERBB2 and cancer: Separation of group 4 and group 5 according to FISH ratios using the various alternative controls did not alter this association for any subgroup by ratio greater than or equal to 2.0, determined with any alternative control probe (eTable 2 in the Supplement), consistent with the interpretation that these alternative control ratios of 2.0 or more do not identify a subgroup of cancers which should be considered for upgrading of HER2 status.