Table 1.

Distribution of aminopeptidase N (APN) expression in human meningiomas. Abbreviation: WHO = World Health Organization.

Immunoexpression score	Meningioma	Atypical meningioma	Anaplastic meningioma
	WHO grade I (n = 13)	WHO grade II (n = 17)	WHO grade III (n = 7)
−	2 (15%)	6 (35%)	3 (42%)
+	4 (31%)	4 (24%)	2 (29%)
++	3 (23%)	5 (29%)	2 (29%)
+++	4 (31%)	2 (12%)	—

−, no expression; +, weak patchy expression; ++, strong focal expression; +++, strong expression in more than 50% of tumor tissue.