Table 3. Meta-analysis results for association between RET/PTC fusion genes and radiation exposure in patients with PTC.

Radiation exposure vs. non-radiation exposure	No. of studies	No. of cases/controls	OR(95%CI)	P value	Model	I2	Pheta
For RET/PTC1 and 3
All	14	537/388	2.82(1.38,5.78)	0.005	Random	74%	<0.001
Region
Asian	4	232/71	0.88(0.26,2.93)	0.833	Random	56%	0.077
Western	10	305/317	3.97(2.03,7.75)	<0.001	Random	59%	<0.001
For RET/PTC1
All	9	285/287	1.86(0.66, 5.28)	0.243	Random	76.00%	<0.001
Region
Asian	1	37/12	0.24(0.06,0.96)	0.043	Random	/	/
Western	8	248/275	2.46(0.83,7.27)	0.104	Random	74.10%	<0.001
For RET/PTC3
Allb	8	243/240	8.30(4.32,15.96)	<0.001	Fixed	0.00%	0.980
Region
Asian	/	/	/	/	/	/	/
Western	8	243/240	8.30(4.32,15.96)	<0.001	Fixed	0.00%	0.980

^aP-value for heterogeneity test;

^bData from Sadetzki et al. [21] and Learoyd et al. [6] showed that the RET/PTC3 gene prevalence was 100% in both the groups with and without radiation exposure and that the OR and standard error could not be estimated; therefore, these studies were excluded. The statistically significant results are highlighted in bold.