Table 1 Criteria used to elevate the quality of included studies in this meta-analysis of six most reported biomarkers (derived from REMARK)

1-Samples

Cohort study with a well-defined study population. Medical treatment for patients was reasonable. Authors provided justification for excluded patients

2- Clinical parameters of the cohort

The clinical parameters such as age, gender, surgical procedure, pathologic stage and histological type was provided

3-Staining Method

Clear staining method such as H&E and IHC was referred to original paper

4-Prognosis

The survival endpoints were defined as overall survival and disease-free survival

5- Statistics

Statistical analysis was univariate or multivariate Cox proportional hazards method

6- Effect size

HR or RR with 95% CI and P-vales were provided