Table 3. HER1-4 and NRG1 levels in normal and breast cancer tissue among postmenopausal patients.

Gene	Menopause stage	Normal tissue	Tumour tissue	Fold change (95% CI)	Tumour versus normal tissuea	P for changeb
EGFR/HER1	Pre	1.31 (1.07-1.62)c	0.14 (0.058-0.32)	0.10 (0.047-0.23)	0↑ 8↓	P=0.012
	Post	1.32 (1.17-1.48)	0.18 (0.12-0.26)	0.13 (0.09-0.20)	0↑ 22↓	P≤0.001
HER2	Pre	0.31 (0.20-0.50)	0.83 (0.52-1.33)	2.64 (1.50-4.63)	7↑ 1↓	P=0.017
	Post	0.27 (0.21-0.34)	0.66 (0.52-0.85)	2.48 (1.70-3.65)	19↑ 3↓	P≤0.001
HER3	Pre	0.062 (0.015-0.26)	1.05 (0.45-2.43)	16.96 (4.02-71.52)	8↑ 0↓	P=0.012
	Post	0.027 (0.012-0.061)	0.60 (0.47-0.78)	22.27 (9.03-54.92)	21↑ 1↓	P≤0.001
HER4	Pre	0.16 (0.10-0.27)	0.25 (0.096-0.67)	1.54 (0.69-3.45)	5↑ 3↓	P=0.123
	Post	0.16 (0.11-0.23)	0.23 (0.11-0.50)	1.30 (0.54-3.16)	17↑ 5↓	P=0.006
NRG1	Pre	0.025 (8.76*10-4-0.72)	0.071 (0.031-0.16)	2.86 (0.11-77.45)	4↑ 4↓	P=0.263
	Post	0.013 (0.0026-0.062)	0.11 (0.045-0.29)	8.97 (1.90-42.40)	14↑ 8↓	P=0.506

^a Number of patients with higher (↑) or lower (↓) tumour compared to normal tissue mRNA levels.

^b P value from Wilcoxon Signed Ranks test for paired samples.

^c mRNA levels presented as geometric mean (95% CI).