Focal Cortical Dysplasia Type II (Malformations of Cortical Development) Aberrantly Expresses Apoptotic Proteins

Abstract

bcl-XL, bax, bcl-2, and p53 are apoptotic proteins essential to normal neural development. Aberrant expression of these proteins has been observed in several central nervous system neoplasms. Immunoexpression of these markers is studied in 21 patients with focal cortical dysplasia type II (Taylor-type cortical dysplasia; malformations of cortical development) who had undergone lesionectomy for treatment of pharmacoresistant epilepsy. Paraffin immunohistochemistry using standard methodology was performed on representative sections using antibodies to bcl-XL, bax, bcl-2, and p53. Aberrant expression of bcl-XL, bax, bcl-2, and p53 was observed in the majority of cases, with dysmorphic neurons staining positively for bcl-XL, bax, and bcl-2 in 71%, 76%, and 24% of cases, respectively, and balloon cells staining positively for bcl-XL, bax, and bcl-2 in 89%, 78%, and 17% of cases, respectively. Most cases (86%) showed some expression of p53, with the majority showing expression of p53 most prominently in balloon cells. Previous work has shown gangliogliomas and dysembryoplastic neuroepithelial tumors, both dysplasia-associated neoplasms, to demonstrate aberrant expression of apoptotic markers, suggesting a possible common mechanism of development for these 2 processes in patients in whom they coexist.