Bcl-2 and bcl-xL are
proteins known to inhibit cell death (apoptosis). Expression of these
proteins in
gangliogliomas has not been extensively examined. This study retrospectively evaluates bcl-2 and bcl-x immunostaining in
paraffin-embedded materials in
gangliogliomas. Twenty-nine
gangliogliomas in 17 males and 12 females, age 2.5 to 47 years (mean, 20.7 years), were studied. Nineteen
tumors were situated primarily in the temporal lobe. All but three patients presented with
seizures ranging from 3 months to 28 years' duration (mean, 11.1 years) before surgery. All
tumors histologically were comprised of an atypical neuronal component and a
glioma component, which most frequently resembled a low-grade
astrocytoma.
Cortical dysplasia was observed adjacent to eight
tumors. MIB-1 (marker of cell proliferation) labeling indices (percentage of positively staining
tumor cell nuclei) ranged from 0 to 7.7 (mean, 0.8). bcl-2 staining was observed in 25
tumors (86%); neuronal staining was present in 24 cases (83%), and glial cell staining in 21
tumors (72%). Bcl-xL staining was only observed in eight
gangliogliomas (28%); in all eight
tumors (28%), neuronal staining was seen, and focal glial cell staining was present in two cases (7%). Four
tumors (14%) did not
stain with either bcl-2 or bcl-xL. There appeared to be no relationship between MIB-1 immunostaining and staining with bcl-2 or bcl-xL. bcl-2 expression by immunohistochemistry was observed more frequently than bcl-xL in
gangliogliomas. Expression of these
proteins may reflect abnormalities of apoptosis, which could play a role in the survival of cells that may be involved in the development of
gangliogliomas.