Table 2. Baseline characteristics of studies associated with the prognosis of RCC included in the meta-analysis.

Ref.	Year	Surname	Ethnicity	Genotyping	Cases	Gene polymorphism	Survival analysis	Source of HR	Max months for follow-up	NOS
[33]	2015	Ma	Asian	PCR-RFLP	310	−2578C/A, −1154G/A, −634C/G	OS	Reported	60	7
[34]	2015	Yang	Asian	PCR-RFLP	336	−2578C/A, −1154G/A, −634C/G	OS	Reported	60	6
[21]	2014	Zhong	Asian	PCR-RFLP	332	−2578C/A, −1154G/A, −634C/G	OS	Reported	60	5
[22]	2007	Kawai	Caucasian	PCR-RFLP	213	−2578C/A, −1154G/A, −634C/G	OS	Reported	160	6

HR: hazard ratio; OS: overall survival; NOS: Newcastle-Ottawa Scale.