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 values 4 | ||||
|---|---|---|---|---|---|---|
| Full methylation | Partial methylation | p values 3 | 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.