Table 4.

Discordant STRAT4-ERRB2 vs IHC-HER2 Cases^a

Case No.	STRAT4-ERBB2	IHC-HER2	HER2 FISH (HER2/Cep17 = Ratio)
1	Negative	Positive (3+)	Negative (3.05/3.1 = 0.98)
2	Positive	Negative (1+)	Positive (9.15/1.65 = 5.55
3	Positive	Negative (1+)	Negative (3.20/2.90 = 1.1)

FISH, fluorescence in situ hybridization; HER2, human epidermal growth factor receptor 2; IHC, immunohistochemistry.

^aTwo STRAT4 results were concordant with FISH, and one IHC result was concordant with FISH. The ratio reports the average HER2 copy number compared with centromere Cep17 copy number. A ratio of 2.0 or more is a positive FISH result.