Table 1.
Lynch syndrome cases of CRC and advanced adenomas tested for SEPTIN9 methylation in tissues
| CRC group (%) | Adenoma group (%) | |
| All unique cases | 36 | 14 |
| Both CRC and adenoma | 4 | 4 |
| Mean age at diagnosis, years (±SD) | 55.28 (±15.63) | 46.7 (±11.0) |
| Sex | ||
| Males | 26 (72.2%) | 7 (50%) |
| Females | 10 (27.8%) | 7 (50%) |
| Gene mutated | ||
| MLH1 | 10 (27.8%)3 | 9 (64.3%)3 |
| MSH2 | 5 (13.9%) | 4 (28.6%) |
| MSH6 | 10 (27.8%)1 | 1 (7.1%)1 |
| PMS2 | 11 (30.6%) | 0 (0.0%) |
| Neoplasia, n* | 37 | 20 |
| Location | ||
| Left sided | 13 (35.1%) | 15 (75%) |
| Right sided | 24 (64.9%) | 5 (25%) |
| Stage | NA | |
| I | 8 (21.6%) | |
| II | 17 (46.0%) | |
| III | 5 (13.5%) | |
| IV | 4 (10.8%) | |
| Unknown | 3 (8.1%) | |
| Immunohistochemistry | ||
| MLH1 | 3 IHC loss, 1 LOH, 6 NT | NT |
| MSH2 | 4 IHC loss, 1 NT | NT |
| MSH6 | 7 IHC loss, 3 IHC weak+somatic mutation† | NT |
| PMS2 | 11 IHC loss† | NT |
| Matched NCM | 29 (28)‡ | 13 (10)‡ |
Numbers in superscript indicate the number of cases who developed synchronous CRC and adenoma.
*Includes one CRC case developing two synchronous CRCs, and five adenoma cases developing two or more synchronous adenomas.
†Immunohistochemistry (IHC) or identification of a somatic second hit in tumour, as previously published.10
‡Number of matched pairs of tumour-NCM with unique NCM samples (some cases developed more than one synchronous neoplasm).
CRC, colorectal cancer; LOH, loss of heterozygosity of normal allele; NA, not applicable; NCM, normal colorectal mucosa; NT, not tested.