IMMUNOHISTOCHEMICAL ANALYSIS OF PROGESTERONE-RECEPTOR AND KI-67 LABELING INDEX IN ASTROCYTIC TUMORS

BACKGROUND. Intracranial tumors such as meningiomas express steroid ho rmone receptors but little is known regarding progesterone receptor (P R) in astrocytic tumors. The authors evaluated expression of PR in 86 astrocytic tumors in relation to tumor proliferative potential. METHOD S. Paraffin embedded tumor sections were stained with polyclonal antip rogesterone antibody by the peroxidase-antiperoxidase method and with monoclonal MIB-1-Ki-67 antibody by avidin-biotin complex immunohistoch emistry. RESULTS. Sixty-three of the 86 astrocytic tumors (73%) showed positive PR immunoreactivity. PR expression was observed in 4 of 9 pi locytic astrocytomas, 13 of 24 Grade 2 astrocytomas, 15 of 20 anaplast ic astrocytomas, and 31 of 33 glioblastomas. In addition to the tumor cells, cells of microvascular endothelial proliferation and the smooth muscle of tumor vessel walls were frequently PR positive. Glioblastom as had a significantly higher percentage of PR positive cells compared with anaplastic (P < 0.0008) and low grade (P < 0.0001) astrocytomas. Patients with PR positive astrocytomas were of an older age than pati ents with PR negative astrocytomas (48.71 +/- 21.95 years vs. 37.09 +/ - 24.69 years; P < 0.04). The mean Ki-67 labeling index (LI) was signi ficantly higher in the high grade (3-4) astrocytomas compared with low grade (1-2) astrocytomas (P < 0.0001). PR positive astrocytic tumors had higher Ki-67 LI than PR negative tumors. PR expression was not cor related with tumor recurrence and patient survival. CONCLUSIONS. The c urrent study suggests that PR in the astrocytic tumors correlates with histologic grade and PR may participate in the growth of these tumors and tumor angiogenesis. The measurement of PR in these tumors may ind irectly represent tumor growth potential. (C) 1997 American Cancer Soc iety.