Table 2. Newcastle-Ottawa Scale Based Quality Assessment of Studies Included in CD44 Meta-Analysis.

Author Name	Selection				Comparability		Exposure			Total scores
	1	2	3	4	1	2	1	2	3
Jiang et al., 2012	*	*	*	*	*	*	*	*	-	8
Tulsyan et al., 2013	*	*	-	*	*	*	*	*	-	7
Xiao et al., 2013	*	*	*	*	*	*	*	*	-	8
Sharma et al., 2014	*	*	-	*	*	*	*	*	-	7
Chou et al., 2014	*	*	-	*	*	*	*	*	-	7
Chou et al., 2014	*	*	-	*	*	*	*	*	-	7
Lou et al., 2014	*	*	-	*	*		*	*	-	6
Weng et al., 2015	*	*	-	*	*		*	*	-	6
Wu et al., 2015	*	*	*	*	*	*	*	*	-	8
Wu et al., 2015	*	*	*	*	*		*	*	-	8
Liu et al., 2015	*	*	-	*	*	*	*	*	-	6
Verma et al., 2016	*	*	-	*	*	*	*	*	-	7

Selection: (1) Adequate definition of cases (yes, with independent validation, one star); (2) representativeness of the cases (if yes, one star); (3) selection of controls (one star for community controls,); (4) definition of controls (if no history of disease, one star). Comparability: comparability of cases and controls on the basis of design or analysis: (1) ethnicity matched (if yes, one star); (2) analysis age adjusted (if yes, one star). Exposure: (1) ascertainment of exposure (if in reliable method, one star); (2), same method of ascertainment for cases and controls (if yes, one star); (3) non-response rate (same rate for both group, one star).