EXPRESSION OF THE C-ERBB-2-ENCODED ONCOPROTEIN AND PROGESTERONE-RECEPTOR IN HUMAN MENINGIOMAS

The present study investigated the expression of c-erbB-2 in 59 mening iomas, including different histological subtypes and anaplastic varian ts, by immunocytochemistry and molecular biological techniques. Immuno histochemistry using the monoclonal antibody FWP-51 directed against c -erbB-2-encoded oncoprotein gp185 demonstrated variable degrees of imm unoreactivity in all meningiomas. The intensity of immunostaining corr elated with the degree of expression as assessed by Western analysis i n 28 meningiomas using polyclonal antiserum 21N. There was no correlat ion between the degree of expression and histological variants. Immuno reactivity of all meningiomas was distinctly less intense, however, th an that of the human breast cancer cell line SK-BR-3, and slightly low er than that of brain metastases of breast and ovarian carcinomas that served as positive controls for both methods. By Southern analysis al l meningiomas showed a single copy of the c-erbB-2 gene. Non-neoplasti c arachnoid cap cells also exhibited c-erbB-2 expression and the degre e of immunoreactivity was comparable with the majority of meningiomas. These data argue against an overexpression of c-erbB-2 in meningiomas , but rather indicate a cell-type-specific constitutive expression of the c-erbB-2 gene product in meningiomas and their putative progenitor cells. Since a subgroup of meningiomas is known to express progestero ne receptors (PR), gp185 immunoreactivity was compared to the hormone receptor status using monoclonal antibody KD68. Fifty-six percent meni ngiomas showed PR immunoreactivity, but there was no statistically sig nificant correlation with the degree of gp185 expression.