Table 2. Characteristics of the included case-control studies on the MTHFR A1298C polymorphism in cervical lesions.

First author[reference]	Year	Source of control	Source of DNA	Country	Ethnicity	HWE	Histology	Sample size		Case						Control
								case	control	A	C	AA	AC	CC	AC+CC	A	C	AA	AC	CC	AC+CC
Tong [26]	2011	Healthy persons	Blood	Korea	Asian	NS	SIL	160	428	260	60	107	46	7	53	688	168	278	132	18	150
							HSIL	160	428	273	47	117	39	4	43	688	168	278	132	18	150
							ICC	148	428	235	61	89	57	2	59	688	168	278	132	18	150
Kohaar [22]	2010	Healthy persons	Tissue or cell	India	Asian	NS	HSIL	39	231	50	28	15	20	4	24	289	173	85	119	27	146
							ICC	164	231	199	129	58	83	23	106	289	173	85	119	27	146
Nandan [27]	2008	Healthy persons	Blood	India	Asian	NA	SIL	80	77	NA	NA	14	NA	NA	66	NA	NA	37	NA	NA	40
							ICC	62	77	NA	NA	20	NA	NA	42	NA	NA	37	NA	NA	40
Kang [23]	2005	Healthy persons	Blood	Korea	Asian	NS	ICC	79	84	132	26	55	22	2	24	141	27	58	25	1	26
Yang [25]	2011	Mixed	Blood	China	Asian	NS	SIL	38	382	62	14	24	14	0	14	606	158	237	132	13	145
							ICC	157	382	245	69	89	67	1	68	606	158	237	132	13	145

Abbreviations: HWE: Hardy-Weinberg Equilibrium; NA, not available; NS, not significant; LSIL, low-grade squamous intraepithelial lesion; HSIL, high-grade squamous intraepithelial lesion; ICC, invasive cervical cancer; SIL, squamous intra-epithelial lesion.