Table 3. Summary ORs of the XPC polymorphism and cancer risk by different control groups, genotyping methods and tumor locations.
| SNP | Variables | Classification | Studies | Case/control | Dominant model |
Recessive model |
Homozygote model |
|||
|---|---|---|---|---|---|---|---|---|---|---|
| OR (95% CI) | P* | OR (95% CI) | P* | OR (95% CI) | P* | |||||
| XPC Lys939Gln rs2228001 | Source of control | Hospital-based | 5 | 2,505/3,094 | 1.19 (0.97-1.46) | 0.02† | 1.15 (0.86-1.56) | 0.01** | 1.27 (0.90-1.80) | 0.007** |
| Population-based | 6 | 2,057/3,499 | 1.13 (1.00-1.26) | 0.71 | 1.18 (1.00-1.39) | 0.89 | 1.24 (1.04-1.48) | 0.970 | ||
| Genotyping method | PCR-RFLP | 7 | 2,133/3,434 | 1.12 (1.00-1.26) | 0.81 | 1.16 (0.99-1.36) | 0.56 | 1.24 (1.04-1.47) | 0.930 | |
| TaqMan | 4 | 2,429/3,159 | 1.20 (0.96-1.50) | 0.01† | 1.24 (0.93-1.64) | 0.03** | 1.33 (0.92-1.92) | 0.005** | ||
| Tumor location | Upper digestive system | 8 | 3,637/4,838 | 1.14 (0.99-1.31) | 0.03 | 1.29 (1.11-1.50) | 0.26 | 1.33 (1.09-1.63) | 0.060 | |
| Lower digestive system | 3 | 925/1,755 | 1.21 (1.02-1.42) | 0.71 | 1.01 (0.75-1.35) | 0.22 | 1.18 (0.92-1.53) | 0.410 | ||
| XPC intron9 PAT | Source of control | Hospital-based | 3 | 602/1,021 | 1.21 (0.66-2.23) | 0.05 | 1.21 (0.98-1.50) | 0.82 | 1.28 (0.76-2.17) | 0.140 |
| Population-based | 4 | 827/1,703 | 0.82 (0.64-1.06) | 0.77 | 0.97 (0.82-1.15) | 0.45 | 0.82 (0.62-1.07) | 0.670 | ||
| Genotyping method | PCR-RFLP/TaqMan‡ | NA | NA | NA | NA | NA | NA | NA | NA | |
| Tumor location | Upper digestive system | 6 | 1,017/1,892 | 0.96 (0.70-1.31) | 0.19 | 1.16 (0.99-1.36) | 0.92 | 1.04 (0.78-1.39) | 0.300 | |
| Lower digestive system§ | 1 | NA | NA | NA | NA | NA | NA | NA | ||
| XPC Ala499Val rs2228000 | Source of control | Hospital-based | 3 | 1,244/1,573 | 0.94 (0.81-1.10) | 0.63 | 1.07 (0.84-1.36) | 0.48 | 1.06 (0.82-1.37) | 0.610 |
| Population-based | 3 | 1,252/2,062 | 0.76 (0.65-0.89) | 0.28 | 0.96 (0.76-1.21) | 0.66 | 0.84 (0.66-1.07) | 0.730 | ||
| Genotyping method | PCR-RFLP | 4 | 1,613/2,678 | 0.80 (0.68-0.93) | 0.23 | 0.96 (0.78-1.18) | 0.84 | 0.86 (0.70-1.07) | 0.860 | |
| TaqMan | 2 | 883/957 | 0.95 (0.78-1.14) | 0.34 | 1.14 (0.83-1.56) | 0.29 | 1.13 (0.82-1.54) | 0.470 | ||
| Tumor location | Upper digestive system | 5 | 2,077/2,797 | 0.84 (0.71-0.98) | 0.13 | 1.06 (0.87-1.27) | 0.76 | 0.98 (0.80-1.19) | 0.640 | |
| Lower digestive system§ | 1 | NA | NA | NA | NA | NA | NA | NA | ||
*Test for Heterogeneity; †Random-effects model was used when P value for het erogeneity test <0.05; otherwise, fixed-effect model was used. **All the articles were genotyping by PCR-RFLP; §, only one article available for lower digestive system