Table 2.
Relation between invasive meningiomas and aminopeptidase N (APN) expression. Abbreviation: WHO = World Health Organization.
| Type of invasion*/APN immunoexpression | Meningioma | Atypical meningioma | Anaplastic meningioma |
|---|---|---|---|
| WHO grade I (n = 13) | WHO grade II (n = 17) | WHO grade III (n = 7) | |
| Brain invasion | − | 4 (24%) | 5 (71%) |
| APN | −:2 | −:4 | |
| +:1 | ++:1 | ||
| +++:1 | |||
| Dural invasion | 4 (31%) | 4 (24%) | 1 (14%) |
| APN | −:1 | −:2 | + |
| +:2 | +:1 | ||
| ++:1 | ++:1 |
*
Bone invasion was not observed. Immunoexpression of APN was graded semiquantitatively: −, no expression; +, weak patchy expression; ++, strong focal expression; +++, strong expression in more than 50% of tumor tissue.