Human papillomavirus infection and gastric cancer risk: A meta-epidemiological review

Table 2 Extracted information of the 18 selected case-control studies

Ref.	Year	Nation	Site	Test	Sample	PCa	NCa	PCo	NCo
Sha et al[19]	1998	China	Gastric	PCR	FFPE	27	38	4	61
Dong et al[20]	1999	China	Gastric	PCR	Other	10	27	0	20
Yu et al[21]	1999	China	Gastric	PCR	FFPE	30	102	3	101
Zhou et al[22]	1999	China	Gastric	PCR	FFPE	19	31	0	20
Zhu et al[23]	2000	China	Gastric	PCR	FF	11	31	0	42
Liao et al[24]	2001	China	Gastric	ISH	Other	26	24	2	28
Xu et al[25]	2003	China	Cardia	ISH	FFPE	50	24	10	40
Xu et al[25]	2003	China	Gastric	ISH	FFPE	111	125	10	40
Ma et al[26]	2007	China	Gastric	PCR	FFPE	15	25	2	38
Ma et al[27]	2007	China	Cardia	PCR	FFPE	32	61	0	21
Rong et al[28]	2007	China	Cardia	PCR	FFPE	16	5	2	19
Wang et al[29]	2013	China	Gastric	PCR	FFPE	20	72	4	82
Su et al[15]	2015	China	Gastric	PCR	Other	1	14	0	15
Anwar et al[30]	1995	Japan	Gastric	PCR	FFPE	23	28	2	10
Erol et al[31]	2009	Turkey	Gastric	PCR	FFPE	17	21	33	73
Cândido et al[32]	2013	Brazil	Gastric	PCR	FFPE	4	36	10	30
Türkay et al[33]	2015	Turkey	Cardia	PCR	FFPE	2	17	0	8
Bozdayi et al[34]	2019	Turkey	Gastric	PCR	Other	20	33	5	21
Leon et al[35]	2019	Ethiopia	Cardia	PCR	FF	11	51	0	56

FF: Fresh frozen tissue; FFPE: Formalin-fixed paraffin-embedded tissue; ISH: In situ hybridization; NCa: Negative in cases; NCo: Negative in controls; PCa: Positive in cases; PCo: Positive in controls; PCR: Polymerase chain reaction.