Table 1. Characteristics of the included studies.

First author	Year	Country	Tumor type	Sample	Reference	Detection method	Sample size	Outcome	Cut-off value
Kaihua Lu [22]	2013	China	NSCLC	tissue	GAPDH	q-PCR	44	OS	0.27
Ming Sun [23]	2014	China	GC	tissue	GAPDH	q-PCR	72	OS	0.377-fold
Lingfei Jia [24]	2014	China	TSCC	tissue	β-actin	q-PCR	76	OS	mean
Zhenye Li [27]	2014	China	NFPAs	tissue	GAPDH	q-PCR	52	—	median
Han Zhuo [25]	2015	China	HCC	tissue	GAPDH	q-PCR	72	OS, RFS	median
Zhizhong Tian [26]	2015	China	osteosarcoma	tissue	GAPDH	q-PCR	64	OS	median
Gang Luo [28]	2015	China	PC	tissue	GAPDH	q-PCR	21	—	NA
Feifei Meng [30]	2016	China	GC	tissue	GAPDH	q-PCR	55	OS	NA
Weili Duan [29]	2016	China	BC	tissue	GAPDH	q-PCR	80	RFS	median

NSCLC: non-small cell lung cancer, GC: gastric cancer (GC), TSCC: tongue squamous cell carcinoma, NFPAs: non-functioning pituitary adenomas, HCC: hepatocellular carcinoma, PC: prostate cancer (PC), BC: bladder cancer; OS: overall survival; RFS: recurrence-free survival.