Helicobacter pylori and Biliary Tract Cancers: A Meta-Analysis

Table 2

Subgroup analysis of H. pylori prevalence in the malignant group compared with the control group.

Subgroup	No. of studies	H. pylori (+) in malignant group n/N (%)	H. pylori (+) in control group n/N (%)	OR (95% CI)	value
Geographic distribution
Asia	7	128/247	93/203	1.54 (0.62–3.86)	0.36
Europe	4	22/62	6/77	9.58 (3.09–29.6)
North America	2	137/164	250/316	2.51 (1.43–4.42)
Specimen types
FFPE	5	17/72	9/92	5.77 (1.75, 19.02)	0.004
Fresh tissue	1	6/11	0/6	15.36 (0.70, 338.48)	0.08
Frozen tissue	2	75/120	52/114	2.31 (1.25, 4.26)	0.007
Bile	4	72/108	19/48	3.08 (0.50, 19.12)	0.23
Serum	3	117/182	296/358	1.22 (0.49, 3.05)	0.68
Detection method
PCR (16s rRNA)	3	9/51	0/69	13.83 (1.58, 121.27)	0.02
PCR (Urease A)	4	73/127	20/67	2.57 (0.56, 11.86)	0.23
PCR (26 kDa protein gene)	2	7/19	3/45	8.17 (1.60, 41.62)	0.01
PCR (Cag A)	1	46/100	52/92	0.66 (0.37, 1.16)	0.15
PCR (Vac A)	2	56/103	57/99	1.33 (0.27, 4.73)	0.87
ELISA	3	117/182	269/358	1.22 (0.49, 3.05)	0.68
Culture	2	0/26	0/43	NA	NA
IHC	2	0/39	0/41	NA	NA
Histology	1	0/19	0/19	NA	NA
Type of malignancy
Chanlogiocarcinoma	8	96/166	54/147	4.18 (2.03, 8.58)
Gallbladder cancer	7	66/226	89/321	1.36 (0.34, 5.44)	0.67
Other biliary tract cancers	2	74/79	201/235	5.93 (1.89, 18.63)	0.002

FFPE: formalin-fixed paraffin-embedded tissues, IHC: immunohistochemistry, ELISA: enzyme-linked immunosorbent assay, PCR: polymerase chain reaction, H. pylori: Helicobacter pylori, Cag A: cytotoxin-associated gene A, and Vac A: vacuolating cytotoxin A.