TABLE 4.

Treatment changes based on discordance in ER, PR, HER2 IHC, and HER2 FISH in all patients

	Major discordance (n, %)	Minor discordance (n, %)	p‐value*
ER (total n)	28	88	<0.001
No	14 (51.2)	87 (100)
Yes	13 (48.2)	0 (0)
Missing	1	1
PR (total n)	123	281	0.10
No	121 (98.4)	271 (100)
Yes	2 (1.6)	0 (0)
Missing	0	9
HER2 IHC (total n)	255	201	0.04
No	249 (97.7)	201 (100)
Yes	6 (2.4)	0 (0)
Missing	0	0
HER2 FISH (total n)	11	NA
No	5 (50.0)
Yes	5 (50.0)
Missing	1

Abbreviations: ER, estrogen receptor, PR, progesterone receptor, HER2, human epidermal growth factor receptor 2, IHC, immunohistochemistry, FISH, fluorescence in situ hybridization; N, number; NA, Not assessed.

^a Fisher's exact test.