Increased CD9 expression predicts favorable prognosis in human cancers: a systematic review and meta-analysis

Table 2 Subgroup analysis and meta-regression of the association between CD9 expression and overall survival in cancer patients

Subgroup	Number of studies	Number of patients	Pooled HR (95% CI)	p value	Heterogeneity		Meta-regression
Subgroup	Number of studies	Number of patients	Pooled HR (95% CI)	p value	I² (%)	p value	p value
Cancer type							0.298
Breast cancer	2	252	0.27 (0.12–0.63)	0.002	0.0	0.761
Digestive system cancer	4	410	0.39 (0.24–0.63)	< 0.001	6.6	0.360
Head and neck cancer	1	34	0.45 (0.20–1.01)	0.052	-	-
Leukemia/lymphoma	2	224	1.17 (0.33–4.09)	0.809	85.7	0.008
Others	2	221	0.39 (0.24–0.65)	< 0.001	15.8	0.276
CD9 detection method							0.015
Flow cytometry	2	224	1.17 (0.33–4.09)	0.809	85.7	0.008
IHC	6	659	0.42 (0.30–0.60)	< 0.001	0.0	0.532
RT-PCR	3	258	0.30 (0.18–0.50)	< 0.001	0.0	0.993
Publication year							0.060
After 2005	4	444	0.74 (0.36–1.53)	0.417	79.6	0.002
Before 2005	7	697	0.33 (0.23–0.48)	< 0.001	0.0	0.708
Race							0.804
Asian	9	995	0.45 (0.26–0.78)	0.004	71.7	< 0.001
Caucasian	2	146	0.54 (0.32–0.91)	0.020	0.0	0.567
Sample size							0.257
Fewer than 110	5	400	0.37 (0.26–0.53)	< 0.001	0.0	0.875
More than 110	6	741	0.57 (0.28–1.18)	0.131	76.5	0.001

CI confidence interval, HR hazard ratio, IHC immunohistochemistry, RT-PCR reverse transcription-polymerase chain reaction

ISSN: 1475-2867