Table 4. Summary ORs (95% CI) for the XRCC1 Arg399Gln polymorphism categorized by histological type or anatomical area in a specific tumor site¹.

Cancer type	Histological type oranatomical area	No. comparisons(SZ case/control)	Dominant model		Recessive model		Additive model
			OR (95% CI)	P h/I 2	OR (95% CI)	P h/I 2	OR (95% CI)	P h/I 2
		4 (1,424/1,428)	1.03 (0.89–1.19)	0.278/22.1%	1.25 (0.94–1.67)	0.992/0.0%	1.26 (0.94–1.69)	0.974/0.0%
	Oral	3 (525/659)	2	<0.001/87.1%	2	0.004/82.3%	2	0.001/86.8%
	Larynx	4 (706/822)	1.39 (0.95–2.02)*	0.036/64.9%	1.17 (0.74–1.84)	0.100/52.0%	1.38 (0.81–2.34)*	0.067/58.1%
	Thyroid	9 (1,705/2,882)	0.87 (0.74–1.03)*	0.092/41.2%	0.89 (0.73–1.09)	0.362/8.8%	0.84 (0.68–1.04)	0.253/21.4%
	Other sites3	17 (3,916/5,868)	0.98 (0.87–1.10)*	0.041/40.8%	0.90 (0.76–1.08)*	0.099/32.1%	0.91 (0.75–1.10)*	0.081/34.5%
Lung cancer	AC4	11 (1,821/5,536)	1.13 (0.92–1.39)*	0.002/64.4%	1.31 (0.92–1.87*)	0.001/66.7%	1.34 (0.89–2.03)*	<0.001/73.3%
	SC5	6 (1,688/4,014)	0.97 (0.75–1.26)*	0.006/69.4%	1.06 (0.89–1.27)	0.225/29.5%	1.10 (0.77–1.57)*	0.058/56.1%
	SCLC6	3 (112/879)	0.75 (0.37–1.55)*	0.088/58.8%	0.67 (0.32–1.43)	0.642/0.0%	0.62 (0.28–1.37)	0.997/0.0%
Gastric cancer	Cardia	6 (1,378/3,879)	2	<0.001/78.3%	1.25 (0.78–2.00)*	0.002/73.0%	1.21 (0.86–1.71)	0.100/45.8%

¹all summary ORs were calculated using fixed-effects models. In the case of significant heterogeneity (indicated by *), ORs were calculated using random-effects models;

²the results were excluded due to high heterogeneity;

³includes a diversity of head and neck cancer not separated by anatomical area in the studies analyzed;

⁴means adenocarcinoma’.

⁵means squamous cell carcinoma;

⁶small cell lung cancer; the bold values indicate that the results are statistically significant.