Table 1

Scale for quality assessment
Criteria Score
Representativeness of cases
 Selected from cancer registry or multiple cancer center sites 2
 Selected from oncology department or cancer institute 1
 Selected without clearly defined sampling frame or with extensive inclusion/exclusion criteria 0
Source of controls
 Population or community based 2
 Both population-based and hospital-based/healthy volunteers/blood donors 1.5
 Hospital-based controls without gastric cancer 1
 Cancer-free controls without total description 0.5
 Not described 0
Ascertainment of gastric cancer
 Histologically or pathologically confirmed 2
 Diagnosis of gastric cancer by patient medical record 1
 Not described 0
Sample size
 >1000 2
 200-1000 1
 <200 0
Quality control of genotyping methods
 Clearly described a different genotyping assay to confirm the data 1
 Not described 0
Hardy-Weinberg equilibrium
 Hardy-Weinberg equilibrium in controls 1
 Hardy-Weinberg disequilibrium in controls 0.5
 No checking for Hardy-Weinberg disequilibrium 0

Peng et al.

Peng et al. Diagnostic Pathology 2014 9:96   doi:10.1186/1746-1596-9-96

Open Data