Haplotype defined by the MLH1-93G/A polymorphism is associated with MLH1 promoter hypermethylation in sporadic colorectal cancers

Table 1 Association between clinicopathological features and MSI status and methylation status of the MLH1 promoter region in sporadic colorectal cancers

	Methylation-positive				Methylation-negative	p values⁴
	Full methylation	Partial methylation	p values³	Total (Full + Partial methylation)	(No methylation)
Numbers of cases	13	47		60	150
Age at onset	72.8 ± 10.6	64.5 ± 10.1	0.012	66.3 ± 10.7	63.9 ± 11.1	NS
Gender
Male	3	25	NS(0.054)	28	100	0.007
Female	10	22		32	50
Tumor location¹
Right	13	15	<0.0001	28	39	0.004
Left	0	32		32	110
Histological type²
well	6	24	NS	30	105	0.04
mod	3	19		22	36
muc	2	3		5	5
por	2	1		3	4
Dukes
A/B	1/10	2/27	NS	3/37	8/75	NS
C/D	1/1	14/4		15/5	51/16
Tumor size (mm)	66.4 ± 35.5	58.2 ± 26.9	NS	60.0 ± 28.9	52.2 ± 22.4	0.04
MSI-H	13	2	<0.0001	15	4	<0.0001

¹right: cecum, ascending colon and transverse colon, left: descending colon, sigmoid colon and rectum.
²well: well-differentiated adenocarcinoma, mod: moderately differentiated adenocarcinoma, por: poorly differentiated adenocarcinoma, muc: mucinous adenocarcinoma.
³P values were analyzed using Pearson’s chi-square test or Student’s t-test between cases with full methylation and cases with partial methylation. NS: not significant. P values of <0.05 were statistically significant.
⁴P values were analyzed using Pearson’s chi-square test or Student’s t-test between methylation-positive cases (full methylation + partial methylation) and methylation-negative cases. NS: not significant. P values of <0.05 were statistically significant.

ISSN: 1756-0500