Table 2 Subgroup analysis of the association between CXCR4 expression and OS according to different parameters
parameters | No. of studies | Cases | HR (95% CI) of OS | P | I2(%) | Effect model |
|---|---|---|---|---|---|---|
Histological type | ||||||
 NSCLC | 11 | 1540 | 1.59(1.40–1.81) |  < 0.001 | 43.2 | Fixed |
 SCLC | 2 | 115 | 1.77(1.00–3.12) | 0.050 | 0 | Fixed |
Geographical area | ||||||
 non-Asian | 3 | 321 | 1.70(1.22–2.39) | 0.002 | 0 | Fixed |
 Asian | 11 | 1424 | 1.57(1.26–1.96) |  < 0.001 | 43.1 | Fixed |
NOS score | ||||||
  ≥ 7 | 7 | 495 | 1.99(1.42–2.78) |  < 0.001 | 0 | Fixed |
  < 7 | 7 | 1250 | 1.59(1.30–1.96) |  < 0.001 | 50.5 | Random |
Subcellular localization | ||||||
 membrane | 2 | 260 | 1.74(1.24–2.45) |  < 0.001 | 0 | Fixed |
 cytoplasm | 3 | 438 | 2.10(1.55–2.84) |  < 0.001 | 0 | Fixed |
 nucleus | 1 | 61 | 0.56(0.05–6.25) | - | - | - |
TNM stage | ||||||
 Stage I-III | 7 | 680 | 1.62(1.32–1.98) |  < 0.001 | 48.5 | Fixed |
 Stage IV | 1 | 170 | 1.67(1.16–2.38) | - | - | - |
Statistical analysis | ||||||
 Univariate analysis | 9 | 883 | 1.81(1.50–2.17) |  < 0.001 | 0 | Fixed |
 Multivariate analysis | 5 | 862 | 1.59(1.09–2.31) | 0.016 | 67.8 | Random |