Table 2.
Comparison of MSI marker expression in 35 pure mucinous carcinomas and 35 grade- and ER-matched IDC-NSTs determined by immunohistochemistry on tissue microarrays
| N | Pure mucinous (n=35) | IDC-NSTs (n=35) | p value* | |
|---|---|---|---|---|
| MLH1 | 70 | 0.999 | ||
| Positive | 35 (100%) | 34 (97.1%) | ||
| Negative | 0 | 1 (2.9%) | ||
| Inconclusive | 0 | 0 | ||
| MSH2 | 70 | 0.999 | ||
| Positive | 33 (94.2%) | 34 (97.1%) | ||
| Negative | 1 (2.9%) | 1 (2.9%) | ||
| Inconclusive | 1 (2.9%) | 0 | ||
| MSH6 | 70 | 0.114 | ||
| Positive | 35 (100%) | 31 (88.6%) | ||
| Negative | 0 | 3 (8.5%) | ||
| Inconclusive | 0 | 1 (2.9%) | ||
| PMS2 | 69 | 0.239 | ||
| Positive | 32 (94.1%) | 35 (100%) | ||
| Negative | 0 | 0 | ||
| Inconclusive | 2 (5.9%) | 0 | ||
| Combination analysis of MSI markers# | 67 | |||
| 1 marker negative | 1 (3%) | 5 (14.7%) | ||
| 2 markers negative | 0 | 0 | ||
| 3 markers negative | 0 | 0 | ||
| 4 markers negative | 0 | 0 |
*
3×2 Fisher's test
#
inconclusive cases excluded
ER: oestrogen receptor; IDC-NSTs: invasive ductal carcinomas of no special type; MLH1: mutL homolog 1; MSH: mutS homolog; MSI: microsatellite instability; PMS2: postmeiotic segregation increased 2.