Table 1. Quality scores analysis of the 52 eligible studies by the European Lung Cancer Working Party score according to studies characteristics.

Studies	Design (/10)	Laboratory method (/10)	Generalizability (/10)	Results analysis	Global score (%)
All (52)	4.0	5.6	6.4	6.0	55.0
Patients number
Spearman r	0.17	0.14	0.10	0.25	0.14
P	0.22	0.32	0.47	0.08	0.32
Evaluable for meta-analysis
Yes (48)	4.0	4.2	6.4	7.5	58.9
No (4)	4.0	5.6	6.4	5.0	52.5
P	0.38	0.15	0.13	0 .36	0.18
Significant results for OS in univariate analysis
Yes (33)	4.0	4.9	5.6	7.5	59.5
No (7)	6.0	4.2	6.4	7.5	60.2
P	0.78	085	0.98	0.81	0.86
Significant results for OS in multivariate analysis
Yes (27)	4.0	5.6	6.4	7.0	55.3
No (10)	4.0	5.6	6.4	6.3	53.6
P	0.36	0.91	0.91	0.63	0.52

Scores distributions are summarized by median values.

OS = overall survival.