P16 gene hypermethylation and hepatocellular carcinoma: A systematic review and meta-analysis

Table 1 Demographic data of studies included in meta-analysis

Study	HCC tissue/control	No. of patients	Country or area	Median age(Yr)	Sex (M/F)	Year of publication
Formeister et al[14]	Tumor/non-tumor tissues	43/45	America	66.28 ± 8.1	37/12	2010
Zhu et al[15]	Tumor/non-tumor tissues	88/88	China	52.7 ± 10.62	78/10	2010
Zhang et al[16]	Tumor/liver cirrhosis/normal liver tissue	120/120/10	China	52.8 ± 10.2	106/14	2008
Xu et al[28]	Tumor/non-tumor tissues from other patients	30/5	China	NR	NR	2006
Liu et al[17]	Tumor/pericancer tissues	50/50	China	48.5	46/4	2006
Qin et al[18]	Tumor/pericancer/non-tumor tissues	20/20/20	China	NR	NR	2004
Lee et al[19]	Tumor/dysplastic nodule/liver cirrhosis/chronic hepatitis tissues	60/22/30/34	Korea	53.8	47/13	2003
Schagdarsurengin et al[20]	Tumor/non-tumor/liver cirrhosis/normal liver tissues	14/14/6/8	Germany	NR	NR	2003
Zhang et al[21]	Tumor/pericancer/normal tissues	83/10/12	China	NR	NR	2002
Yu et al[22]	Tumor/pericancer tissues	29/29	China	NR	NR	2003
Saito et al[24]	Tumor/non-tumor tissues	59/48	Japan	61 ± 12	42/7	2001
Zhang et al[27]	Tumor/pericancer tissues	35/35	China	NR	NR	2002
Kondo et al[23]	Tumor/non-tumor tissues	40/40	Japan	20-77	32/8	2000
Wong et al[25]	Tumor/non-tumor tissues from other patients	25/35	Hong Kong	NR	NR	2000
Liew et al[26]	Tumor/non-tumor tissues	48/30	Hong Kong	NR	NR	1999