Aberrant GSTP1 promoter methylation is associated with increased risk and advanced stage of breast cancer: a meta-analysis of 19 case-control studies

Table 2 Overall and subgroups analyses of GSTP1 methylation and breast cancer risk

Study groups	Number	OR (95 % CI)	Heterogeneity
Study groups	Number	OR (95 % CI)	Ph	I² (%)	χ²
Overall	19	7.85 (5.12, 12.01)	0.20	21	22.69
Ethnicity
Caucasians	10	7.23 (3.76, 13.90)	0.67	0	6.65
Asians	7	11.71 (5.69, 24.07)	0.61	0	4.53
Sample type
Tissue	14	10.32 (5.97, 17.85)	0.58	0	11.39
Blood	5	4.02 (1.12, 14.38)	0.07	54	8.64
Method
Quantitative	8	4.73 (1.84, 12.12)	0.08	45	12.84
Semi-quantitative	4	10.33 (3.32, 32.10)	0.86	0	0.77
Non-quantitative	7	12.55 (5.72, 27.55)	0.61	0	4.51

ISSN: 1471-2407