Promoter hypermethylation of the SFRP2 gene is a high-frequent alteration and tumor-specific epigenetic marker in human breast cancer

Table 1 Clinicopathological and immunohistochemical factors in relation to SFRP2 immunoreactivity

	SFRP2 immunoreactivity
Variable	n ^a	IRS 0 – 4 (%)	IRS > 4 (%)	R ^d	P ^e
Total	125	93 (74)	32 (26)
*Clinicopathological factors*
Age at diagnosis (median: 57 years; range 29 – 82 years)
< 60 years	69	49 (71)	20 (29)	-0.103	0.255
≥ 60 years	55	44 (80)	11 (20)
Tumor size^b
pT1	42	29 (69)	13 (31)	-0.110	0.226
pT2 – 4	81	64 (79)	17 (21)
Lymph node status^b
pN0	62	41 (66)	21 (34)	-0.194	0.033
pN1 – 3	59	49 (83)	10 (17)
Histological grade
G1 – G2	67	49 (73)	18 (27)	-0.047	0.606
G3	57	44 (77)	13 (23)
Histological type
ductal	98	73 (75)	25 (26)	0.024	0.796
lobular	9	9 (100)	0 (0)
other	14	9 (64)	5 (36)
*Immunohistochemistry*
Estrogen receptor status
negative (IRS^c 0 – 2)	28	20 (71)	8 (29)	-0.079	0.424
positive (IRS 3 – 12)	76	60 (79)	16 (21)
Progesterone receptor status
negative (IRS^c 0 – 2)	72	55 (76)	17 (24)	0.048	0.611
positive (IRS 3 – 12)	43	31 (72)	12 (28)
Her2
negative (0, 1+)	91	70 (77)	21 (23)	0.110	0.238
positive (2+, 3+)	26	17 (65)	9 (35)
p53
negative (< 5%)	70	53 (76)	17 (24)	0.033	0.724
positive (≥ 5%)	44	32 (73)	12 (27)

^aOnly female patients with primary, unilateral, invasive breast cancer were included. ^bAccording to UICC: TNM Classification of Malignant Tumours [38]. ^cIRS = immunoreactivity score according to Remmele and Stegner [40]. ^dPearson's correlation coefficient. ^eFisher's exact test (two-sided). Significant P-values are marked in bold face. Percentages may not sum to 100 due to rounding.

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