Table 1.
Prevalence of mismatch repair (MMR) deficiency and immunohistochemical staining patterns in resected and biopsied adenocarcinoma samples
| Immunohistochemistry results | Resections N (%) |
Biopsies N (%) |
| MMR proficient | 243 (73.2) | 58 (85.3) |
| MMR deficiency—complete tumour | 74 (22.3) | 3 (4.4) |
| MLH1/PMS2 | 42 | 3 |
| PMS2 only | 7 | 0 |
| MSH2/MSH6 | 19 | 0 |
| MSH6 only | 6 | 0 |
| Subclonal MMR deficiency | 7 (2.1) | 0 (0) |
| MLH1/PMS2 | 4 | |
| MSH6 only | 1 | |
| All four deficient | 2 | |
| No tumour, excluded from further analysis | 8 (2.4) | 7 (10.3) |
| Total | 332 | 68 |