Table 2. Main results of eligible studies evaluating RASSF1A hypermethylation and OS/DFS in breast cancer patients.

	N. of studies/cases	HR (95% CI)	Heterogeneity
			χ2	p	I2
Overall Survival (OS)
All studies
Fixed effects	5/1439	2.10 (1.45–3.03)	14.67	0.005	72.70%
Random effects	5/1439	3.47 (1.44–8.34)	14.67	0.005	72.70%
Cox regression model	4/1346	3.35 (1.14–9.85)	12.63	0.006	76.20%
Testing methods
QMSP	3/1246	3.28 (0.94–11.50)	12.14	0.002	83.5%
MSP	2/192	4.26 (1.65–10.98)	0.00	0.959	0.00%
Testing materials
Plasma	2/576	6.03 (2.77–13.11)	0.06	0.801	0.00%
Tissue samples	3/863	2.27 (0.82–6.27)	5.46	0.065	63.4%
Disease-Free Survival (DFS)
All studies
Fixed effects	8/1795	2.75 (1.96–3.84)	6.01	0.539	0.00%
Cox regression model	6/1624	2.54 (1.77–3.66)	4.28	0.51	0.00%
Testing methods
QMSP	5/1525	2.77 (1.84–4.15)	3.44	0.487	0.00%
MSP	3/270	2.71 (1.49–4.91)	2.57	0.277	22.1%
Testing materials
Plasma	2/576	3.74 (1.93–7.26)	0.26	0.610	0.00%
Tissue samples	5/1041	2.54 (1.57–4.13)	4.62	0.328	13.5%

MSP, methylation specific PCR; QMSP, quantitative methylation specific PCR.