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

Table 3 Univariate survival analysis of clinicopathological and immunohistochemical parameters with SFRP2 promoter methylation

	Disease-free survival (DFS)			Overall survival (OS)
Variable	n ^a	Events	P ^b	n ^a	Events	P ^b
*Clinicopathological factors*
Age at diagnosis
< 60 years	84	33	0.391	83	15	0.414
≥ 60 years	52	18		53	13
Tumor size^c
pT1	51	16	0.059	51	8	0.165
pT2 – 4	82	35		82	20
Lymph node status^c
pN0	59	15	0.008	59	7	0.026
pN1 – 3	66	31		66	18
Histological grade
G1 – G2	72	19	0.003	73	7	0.001
G3	61	32		61	21
Histological type
ductal	109	35	0.009	109	25	0.622
lobular	18	9		18	2
other	9	7		9	1
*Immunohistochemistry*
Estrogen receptor
negative (IRS^d 0 – 2)	47	16	0.644	46	12	0.118
positive (IRS 3 – 12)	84	35		85	16
Progesterone receptor
negative (IRS^d 0 – 2)	44	19	0.318	45	12	0.093
positive (IRS 3 – 12)	87	32		86	16
*SFRP2 promoter*
unmethylated	23	5	0.192	23	5	0.686
methylated	113	45		113	23

^aOnly female patients with primary, unilateral, invasive breast cancer were included. ^bUnivariate log-rank test (two-sided). ^cAccording to UICC: TNM Classification of Malignant Tumours [38]. ^dIRS = immunoreactivity score [40]. Significant P-values marked in bold face.

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