Table 3. Analysis of MLH1 methylation using MS-MLPA in samples from the proband and relatives.
| % MLH1 methylation | |||||||
|---|---|---|---|---|---|---|---|
| Family | Individual | Sample | A region (−659) | B region (−383) | C region (−246) | D region (−13) | Intron 1 (+208) |
| A | I.1 | PBL | 0 | 0 | 0 | 0 | 0 |
| II.1 (case 1) | CRC 1 | 61.2 | 83.7 | 57.6 | 59.7 | 60.9 | |
| CRC 2 | 62.3 | 86.9 | 60.5 | 62.8 | 63.5 | ||
| PBL | 60.5 | 76.7 | 56.0 | 56.2 | 60.2 | ||
| fibroblasts | 55.8 | 53.2 | 64.0 | 52.4 | 63.0 | ||
| colonic mucosa | 52.3 | 78.9 | 58.3 | 48.5 | 62.6 | ||
| sperm | 0 | 0 | 0 | 0 | 0 | ||
| II.2 | PBL | 0 | 0 | 0 | 0 | 0 | |
| III.1 | PBL | 0 | 0 | 0 | 0 | 0 | |
| III.2 | PBL | 0 | 0 | 0 | 0 | 0 | |
| B | case 34 | EC | 33.6 | 59.4 | 26.1 | 37.3 | 28.5 |
| CRC | 58.0 | 56.3 | 55.5 | 48.8 | 56.4 | ||
| PBL | 35.9 | 45.3 | 25.1 | 27.6 | 27.7 | ||
| RKO | 110.1 | 113.2 | 103.0 | 88.2 | 103.4 | ||
Peripheral blood lymphocytes (PBL), skin fibroblasts, colorectal tumors (CRC 1 and 2), normal adjacent mucosa and sperm from case 1 (II.1), PBL from his relatives, and PBL, CRC and endometrial cancer (EC) from case 34, were analyzed. DNA from RKO cell line (methylated in MLH1) is used as a positive control. Representative data from two independent experiments is shown. Methylation levels above 20% are shown in bold.