Table 2.

Clinicopathological parameters in relation to ID4 promoter methylation

Variable	ID4 Methylation
	na	Positive	Negative	P-valued
Total	170	117	53
Clinicopathological parameters:
Age at diagnosis
<50 years	51	34	17	0.821
≥ 50 years	111	76	35
Tumour sizeb
pT1	62	24	44	0.247
pT2-4	91	27	7
Lymph node statusb
pN0	74	43	31	0.030
pN1-3	62	47	15
Histological grade
G1	14	10	4	0.944
G2	79	52	27
G3	61	42	19
Histological type
invasive ductal	129	87	42	0.940
invasive lobular	18	12	6
other	12	8	4
Oestrogen receptor status
negative (IRSc 0–2)	52	35	17	0.900
positive (IRS 3–12)	101	69	32
Progesterone receptor status
negative (IRS 0–2)	57	39	18	0.920
positive (IRS 3–12)	96	65	31
ID4 mRNA expression x-fold
FC<2	8	0	8	<0.001
FC≥2	38	31	7

^a Only female patients with primary, unilateral, invasive breast cancer were included. Significant P- values are marked in bold face. ^bAccording to TNM classification by Sobin and Wittekind [37]. ^c IRS = Immuno-reactive score according to Remmele and Stegner [38]. ^dFisher's exact test. Significant P- values are marked in bold face.